Important Questions for Class 10

Science

Chapter 3 – Metals and Non-Metals

Very Short Answer Questions 1 Mark

1. A mineral is known as ore if metal
(a) Cannot be produced from it
(b) Can be produced from it
(c) Can be extracted from it profitably
(d) Is very costly
Ans: (c) Can be extracted from it profitably

2. The earthy impurities associated with minerals used in metallurgy are called
(a) Slag
(b) Flux
(c) Gangue
(d) Ore
Ans: (c) Gangue

3. A basic lining is given to a furnace by using

(a) Calcined dolomite
(b) Copper sulphate
(c) Haematite
(d) Silica

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Ans: (a) Calcined dolomite

4. Malachite is an ore of:

(a) Iron
(b) Copper
(c) Mercury
(d) Zinc
Ans: (b) Copper

5. Metal always found in free state is:

(a) Gold
(b) Silver
(c) Copper
(d) Sodium
Ans: (a) Gold

6. A process employed for the concentration of sulphide ore is

(a) Froth floatation
(b) Roasting
(c) Electrolysis
(d) Bessemerisation
Ans: (a) Froth floatation

7. The slag obtained during the extraction of copper pyrites is composed mainly
of
(a) Cu2S

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(b) FeSiO3

(c) CuSiO3

(d) SiO2

Ans: (b) FeSiO3

8. The common method for extraction of metals from the oxide ore is
(a) Reduction with carbon
(b) Reduction with hydrogen
(c) Reduction with aluminium
(d) Electrolytic method
Ans: (a) Reduction with carbon

9. An iron nail was suspended in CuSO4 solution and kept for a while the
solution is
(a) Remained blue and coating was found on the nail.
(b) Turned green and a coating was formed on the nail
(c) Remained blue and no coating was formed on the nail
(d) Turned green and no coating was formed on the nail
Ans: (b) Turned green and a coating was formed on the nail

10. The sulphide ore among the following is

(a) Haematite
(b) Bauxite
(c) Argentite
(d) Zinc blende

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Ans: (d) Zinc blende

11. Chemically rust is

(a) Hydrated ferrous oxide
(b) Hydrated ferric oxide
(c) Only ferric oxide
(d) None of these
Ans: (b) Hydrated ferric oxide

12. Heating pyrites to remove sulphur is called

(a) Smelting
(b) Calcination
(c) Liquation
(d) Roasting
Ans: (d) Roasting

13. Setting of Plaster of Paris takes place due to

(a) Oxidation
(b) Reduction
(c) Dehydration
(d) Hydration
Ans: (d) Hydration

14. Some crystals of CuSO4 were dissolved in water. The color of the solution
obtained would be
(a) Green
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(b) Red
(c) Blue
(d) Brown
Ans: (c) Blue

15. Most abundant metal on the surface of the earth

(a) Iron
(b) Aluminium
(c) Calcium
(d) Sodium
Ans: (b) Aluminium

16. Zone refining is used for the

(a) Concentration of an ore
(b) Reduction of metal oxide
(c) Purification of metal
(d) Purification of an ore
Ans: (c) Purification of metal

17. Which of the following processes is used for the concentration of Bauxite
(Al 2O3 .2H2O)

(a) Froth floatation

(b) Leaching
(c) Liquation
(d) Magnetic separation
Ans: (b) Leaching
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18. During smelting, an additional substance is added which combines with
impurities to form a fusible product. It is known as –
(a) Slag
(b) Mud
(c) Gangue
(d) Flux
Ans: (d) Flux

19. The luster of a metal is due to

(a) Its high density
(b) Its high polishing
(c) Its chemical inertness
(d) Presence of free electrons.
Ans: (d) Presence of free electrons.

20. In the thermite process, the reducing agent is

(a) Nickel
(b) Zinc
(c) Sodium
(d) Aluminium
Ans: (d) Aluminium

21. In addition to iron, stainless steel contains:

(a) Nickel and Chromium
(b) Copper and Tin
(c) Aluminium and Magnesium

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(d) Carbon and Magnesium
Ans: (a) Nickel and Chromium

22. The correct decreasing order of the metals in the activity series is:
(a) Ca,Mg,Ni,Fe

(b) Ni,Ca,Mg,Fe

(c) Ca,Mg,Fe,Ni

(d) Mg,Ca,Fe,Ni

Ans: (c) Ca,Mg,Fe, Ni

23. Which of the following oxides is amphoteric in nature?

(a) Na2O

(b) MgO

(c) CaO
(d) Al 2O3

Ans: (d) Al2O3

24. A student adds one big iron nail each in four test tubes containing a solution
of zinc sulphate, aluminium sulphate, copper sulphate, and iron sulphate. A
reddish-brown coating was observed only on the surface of the iron nail
which was added in the solution of:
(a) Zinc Sulphate
(b) Iron Sulphate
(c) Copper Sulphate
(d) Aluminium Sulphate
Ans: (c) Copper Sulphate
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25. An iron nail was kept in a solution kept in a test tube. After half an hour it
was observed that the color of the solution was changed. The solution in the
test tube was that of:
(a) Zinc Sulphate
(b) Iron Sulphate
(c) Copper Sulphate
(d) Aluminium Sulphate
Ans: (c) Copper Sulphate

26. Name two metals that are found in nature in the free state.
Ans: Gold and Platinum

27. What chemical process is used for obtaining a metal from its oxide?
Ans: The chemical process that is used for obtaining a metal from its oxide is called
reduction. Here, the oxide of the metal will be reduced to the metal with the help of
reducing agents or with substitution reactions with another highly reactive metal.

28. Which of the following pairs will give displacement reactions?

(a) NaCl solution and copper metal
(b) MgCl 2 solution and aluminum metal

(c) FeSO4 solution and silver metal

(d) AgNO3 solution and copper metal

Ans: AgNO3 solution and copper metal

29. Which of the following method is suitable for preventing an iron fry pan from
rusting?
(a) Applying grease

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(b) Applying paint
(c) Applying a coating of zinc
(d) All of the above
Ans: (c) Applying a coating of zinc

30. An element reacts with oxygen to give a compound with a high melting point.
This compound is also soluble in water. The element is likely to be
(a) Calcium
(b) Carbon
(c) Silicon
(d) Iron
Ans: (a) Calcium

31. Food cans are coated with tin and not zinc because
(a) Zinc is costlier than tin
(b) Zinc has higher melting point
(c) Zinc is more reactive than tin
(d) Zinc is less reactive than tin
Ans: (c) Zinc is more reactive than tin

32. What types of oxides are formed when non-metals combine with oxygen?
Ans: When non-metals combine with oxygen they result in the formation of acidic
oxides.

33. Royal water is prepared by mixing two acids ‘A’ and ‘B’. It can dissolve gold
and platinum. It is a highly corrosive and fuming liquid. Identify ‘A’ and ‘B’.
What is the ratio in which ‘A’ and ‘B’ are mixed?

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Ans: Acid ‘A’ is Hydrochloric Acid (HCl) and acid ‘B’ is Nitric Acid (HNO3 ) . The
ratio in which ‘A’ (HCl) and ‘B’ (HNO3 ) are mixed is 3:1 .

Short Answer Questions 2 Marks

1. Which gas is produced when a metal reacts with dilute hydrochloric acid?
Write the chemical reaction when iron reacts with dilute H2SO4 .

Ans: When a metal reacts with dilute hydrochloric acid, hydrogen gas (H2 ) is
produced.
The chemical reaction when iron reacts with dilute H2SO4 is as follows:

Fe(s)  2HCl(dil)  FeCl2 (aq)  H2 (g)

This reaction involves the formation of ferric chloride salt (FeCl2 ) and the liberation
of hydrogen gas (H2 ) .

2. What would you observe when Zinc is added to a solution of Iron (II)
sulphate? Write chemical reaction that takes place.
Ans: When Zinc is added to a solution of Iron (II) sulphate, the color of the solution
changes from green to colorless. This happens because, zinc being more reactive than
iron, displaces iron from iron sulphate and form the colorless zinc sulphate solution,
and the iron gets precipitated at the bottom, in the form of a grey-colored precipitate.
The chemical reaction when Zinc is added to a solution of Iron (II) sulphate is:

Zn(s)  FeSO4 (aq)  ZnSO 4 (aq)  Fe(s) 

3. Why do ionic compounds have high melting points?

Ans:
● Ionic compounds have a high melting point because of the strong forces of
attraction between the oppositely charged cations and anions.
● Typically, ionic compounds have an equal number of cations and anions that are
tightly packed and arranged in a three-dimensional lattice to form their crystalline
structures, which also attributes to their high melting points.
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4. Why sodium is kept immersed in kerosene oil?
Ans: Sodium is highly reactive in nature. It reacts vigorously with both air and water
and burns. So it is kept immersed in kerosene oil to avoid contact with air and water.

5. State two ways to prevent the rusting of iron.

Ans:
(i) By coating the surface of iron with oil, grease, or paint
(ii) By depositing a layer of zinc on the surface of iron, through the process of
galvanization.

6. What type of oxide ore is formed when non-metals combine with oxygen?
Ans: The type of oxide formed when non-metals combine with oxygen is acidic in
nature. When these oxides are dissolved in water, the resulting solution turns blue
litmus red.
Example – C  O 2 
heat
CO 2

7. What are amphoteric oxides? Give examples?

Ans: Amphoteric oxides are oxides that behave as both acidic and basic oxides. They
can neutralize both acids and bases.
They undergo neutralization reaction to form water and salt when reacting with acid
and form complex salts and water when reacting with base.
Examples – Aluminium oxide (Al2O3 ) and Zinc Oxide (ZnO)

8. Name two metals that can displace hydrogen from dilute acids and two metals
which cannot do so?
Ans:
● Metals that can displace hydrogen from dilute acids are Sodium and Calcium.
● Metals that cannot displace hydrogen from dilute acids are Copper and Silver.

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9. Give the reason why platinum, gold, and silver are used to make jewelry.
Ans:
● Platinum, gold, and silver are used to make jewelry due to their low reactivity.
These metals are placed at the bottom of the activity series and are also called noble
metals.
● They do not corrode when exposed to air, water, or chemicals. Thus they do not
lose their shine and have a bright luster, which makes them suitable for making
jewelry.
● These metals are also highly malleable and ductile, so they can be shaped and
designed as required.

10. Why copper is used to make hot water tanks and not steel?
Ans: Copper is used to make hot water tanks, rather than steel because it is a good
conductor of heat than steel. Also copper does not react with cold or hot water, or
even with steam, while the iron component of steel (steel is an alloy of iron), reacts
with steam and forms ferrous oxide. This makes the steel tank weak. Thus copper is
used to make hot water tanks and not steel.

11. Can all minerals of a metal act as ores? Justify.

Ans: Ores are minerals that have a higher concentration of certain elements, while a
mineral is a naturally occurring inorganic solid with definite chemical composition
and crystalline structure.
A mineral can be considered as an ore when a metal can be extracted commercially
from that mineral. But not all minerals are ores, because they can contain unwanted
substances as well. Thus we can say that all ores are minerals, but not all minerals are
ores.

12. How does Galvanization check rusting of iron?

Ans: Galvanization is the method of coating the surface of the iron with a thin layer
of zinc preventing iron from coming in contact with moisture.
In the activity series zinc lies above iron, so it acts as a sacrificial metal, i.e. it oxidizes
instead of iron when exposed to the moisture, thus prevents iron from rusting.
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13. Metals are arranged in the reactivity series. Why hydrogen is kept in the
series though it is not a metal?
Ans: Hydrogen being a non-metal is placed in the reactivity series because its
reactivity is similar to that of an electropositive element, say metals i.e. can lose
electrons to form positive ions. Since hydrogen has one electron in its valence shell,
it can lose its electron and become electropositive (H  ) .

14. Why are metals generally lustrous?

Ans: Metals are generally lustrous because of the flow of free electrons. These
electrons can move freely through the metal, which can absorb the photons from light
falling on their surface. After absorption, these electrons then release the energy as
light, making the metal lustrous.
Also, the free electrons can reflect the light falling on them in the form of diffuse
reflection, making the metal surface appear shiny.

15. Corrosion of metals is not always harmful. Illustrate.

Ans: Corrosion of metals is a harmful process that results in the destruction of metal.
But in certain cases, corrosion is actually advantageous.
Consider the case of corrosion of aluminium. When aluminium corrodes, it forms a
layer of aluminium oxide (Al2O3 ) over the metal. This oxide layer deposited on its
surface acts as a protective coating and prevents further corrosion of the metal from
the attacks of water, air, acids, or alkalis.

16. Why does copper not liberate hydrogen on reacting with dilute sulphuric
acid?
Ans: Copper does not liberate hydrogen on reacting with dilute sulphuric acid because
copper lies below hydrogen in the activity series. Due to this, copper cannot displace
hydrogen from the acid, i.e. it cannot lose electrons to H  ions and liberate hydrogen
gas as other metals do.
17. Why are non-metals gaseous at room temperature?
Ans: The reason why non-metals are gaseous at room temperature is because of their
mostly filled electronic structure. In their molecular form, non-metals exist as
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monoatomic or diatomic molecules like H2 ,O2 , N2 ,Cl2 ,CO2 , etc. Their atoms are
covalently bonded in a molecule, while the intermolecular forces of attraction are
weak that can be easily overcome at room temperature. Therefore, they exist as gases
at room temperature.

18. Both calcium and magnesium are heavier than water but still float over it.
Explain.
Ans: The density of Calcium is 1.74g / cc and that of Magnesium is 1.55g / cc while
the density of water is 1.0g / cc at room temperature. And yet, both metals float over
the water surface. It is because they react with water to produce metal-hydroxide,
Ca(OH)2 ,Mg(OH)2 respectively, and hydrogen gas (H2 ) . The hydrogen gas, in the
form of bubbles, sticks on the metal surface and makes them float above water.

19. What is thermit reaction?

Ans: Thermit reactions are highly exothermic displacement reactions between a metal
and metal oxide. The heat released in this exothermic reaction is so large, that the
metal is obtained in its molten state.
The most common thermit reaction is between ferric oxide with aluminium metal,
which is used to join railway tracks or cracked machine parts.
Reaction – Fe 2O3 (s)  2Al(s) 
heat
2Fe(l)  Al 2O 3 (s)  heat

20. Write the equation for the reaction of

(i) Iron with steam
Ans: Iron with steam – 3Fe  4H2O  Fe3O4  H2

(ii) Calcium and potassium with water

Ans: Calcium with water – Ca  2H2O  Ca(OH)2  H2

Potassium with water – 2K  2H2O  2KOH  H2

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21. Which gas is produced when dilute hydrochloric acid is added to reactive
metal?
Ans: Hydrogen gas is produced when dilute hydrochloric acid is added to a reactive
metal.
Example – Iron reacts with dilute hydrochloric acid to produce iron sulphate and
hydrogen gas.

Fe  2HCl  FeCl2  H 2 

22. Which metals do not corrode easily?

Ans: Noble metals which are at the bottom of activity series like silver, gold, and
platinum do not corrode easily.

23. What are alloys?

Ans: An alloy is a homogeneous mixture of two or more metals, or a metal and a
nonmetal. It is prepared by first melting the primary metal, and then, dissolving the
other elements in it in definite proportions. It is then cooled to room temperature.
Examples – Brass is an alloy of copper and zinc (Cu and Zn), and bronze is an alloy
of copper and tin (Cu and Sn).

24. In the electrolytic refining of a metal M, what would you take as the anode,
the cathode, and the electrolyte?
Ans:
● Anode – a rod of impure metal M.
● Cathode – thin strips of pure metal M.
● Electrolyte – the salt solution of metal M.

25. A metal acts as a good reducing agent. It reduces Fe2O3 and MnO2 . The
reaction with Fe2O3 is used for welding broken railway tracks. Identify &
the metal and write all the chemical reactions.

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Ans: The metal that acts as a good reducing agent, reducing Fe2O3 and MnO2 is
Aluminum.
The thermit reaction between ferric oxide Fe2O3 with aluminium metal is used for
welding broken railway tracks.
Reactions –
Fe 2O3 (s)  2Al(s) 
heat
2Fe(l)  Al 2O 3 (s)  heat

3MnO 2 (s)  4Al(s) 

heat
Mn(l)  2Al 2O 3 (s)  heat

26. A yellow-colored powder ‘X’ is soluble in carbon disulfide. It burns with a

blue flame, forming suffocating smelling gas which turns moist blue litmus
red. Identify ‘X’ and gives a chemical reaction. Identify whether it is a metal
or non-metal.
Ans: The yellow-colored powder ‘X’ is sulfur.
Sulfur is soluble in carbon disulfide.
Sulfur burns in oxygen with a blue flame to form sulfur dioxide, which has a
suffocating smell.
Reaction – S(s)  O2 (g)  SO2 (g)

SO2 turns moist blue litmus red, as it is acidic in nature.

Sulfur is a non-metal.

27. A student set up an electric circuit as shown in Fig. He placed the metal to be
tested in the circuit between terminals A and B as shown.

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(i) Does the bulb glow? What does this indicate?
Ans: Yes, the bulb glows when a metal is placed between terminals A and B. This
indicates that metal is a good conductor of electricity.

(ii) Why are electric wires coated with rubber-like materials?

Ans: Electric wires are coated with rubber-like materials because rubber is a poor
conductor of electricity/ it acts as an insulator, which protects the person from getting
electric shock due to current flow.

28. A, B and C are 3 elements that undergo chemical reactions according to the
following equations:
a) A2O3  2B  B2O3  2A

b) 3CSO4  2B  B2 (SO4 )3  3C

c) 3CO  2A  A2O3  3C

Answer of the following:

(i) Which element is most reactive?
Ans: Hint – a more reactive element will replace a lesser reactive element.
From reactions (a) and (b), we can say that the most reactive element is B because it
can replace both A and C from their compounds.

(ii) Which element is least reactive?

Ans: From reactions (b) and (c), we can say that element C is the least reactive as it
has been replaced both by A and B.

29. An element X on reacting with O 2 forms the oxide (XO2 ) . This oxide
dissolves in water and turns blue litmus paper red. Predict the nature of the
element whether it is a metal or a non-metal.
Ans: The oxide is acidic in nature because it turns blue litmus to red.
Thus element X is a non-metal.

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30. An element E combines with O 2 to form an oxide E2O , which is a good
conductor of electricity. Answer the following:
(i) How many electrons will be present in the outermost shell of E?
Ans: The number of electrons in the outermost shell of element E is 1 . Here, the
valency of oxygen is 2 . Since the oxide formed is E 2O , it means that the valency of
E is1 , i.e. E has only one electron in the valence shell.

(ii) Write the formula of the compound formed when it combines with Chlorine.
Ans: It is known that the valency of Chlorine is 1 and since the valency of E is also
1 , the resultant compound is ECl .
Reaction – E   Cl  ECl

Short Answer Questions 3 Marks

1. Arrange the following metals in decreasing order of their reactivity:
(1) Cu,Ca,Mg,Na,Zn

Ans: The decreasing order of reactivity is – Na > Ca > Mg > Zn > Cu

(2) You are provided with three metals: sodium, magnesium, and copper. Using
only water as the reactant, how will you identify each of them?
Ans: With water as the only reactant we can distinguish Sodium, Magnesium, and
Copper:
a. Sodium reacts vigorously with cold water and burns.
b. Magnesium is not reactive with cold water, but reacts with hot water and produces
hydrogen gas bubbles, and floats to the surface.
c. Copper remains unaffected or unreactive with neither cold nor hot water.

(3) Which metal listed in (1) is most likely to occur in the native state?

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Ans: Copper metal is the one that is most likely to occur in the native state, because
it is at the bottom of the activity series, meaning it is least reactive.

2. Which method of concentration of ore is preferred in the following cases and

why?
(1) The ore has higher density particles mixed with a large bulk of low-density
impurities.
Ans: The concentration of ore can be done by gravity separation method or hydraulic
washing, because of the difference in densities, the low-density impurities can be
washed away, while the high-density ore particles would settle down.

(2) The ore consists of copper sulphide intermixed with clay particles.
Ans: The concentration of ore is done by froth floatation process because of the
difference in the wetting characteristic of the metal and clay particles with oil and
water.

(3) Give an example of amalgam.

Ans: An alloy, with one of the metals as mercury, is called amalgam. An example of
amalgam is the mixture of mercury with silver which is used to fill dental cavities.

3.
(a) Why is ZnO called an amphoteric oxide? Name another amphoteric oxide.
Ans: Amphoteric oxides are oxides that behave as both acidic and basic oxides. They
can neutralize both acids and bases.
They undergo neutralization reaction to form water and salt when reacting with acid
and form complex salts and water when reacting with base.
Zinc oxide (ZnO) is an amphoteric oxide because it behaves both as acidic and basic
oxide.
Reaction:

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As acidic oxide –
ZnO(s)  2NaOH(aq)  Na 2 ZnO2 (aq)  H 2O(l)
ZincOxide(acid)  SodiumHydroxide(alkali)  SodiumZincate(salt)  water

As basic oxide –
ZnO(s)  2HCl(aq)  ZnCl2 (aq)  H 2O(l)
ZincOxide(alkali)  HydrochloricAcid(acid)  ZincChloride(salt)  water

(b) What are alkalis? Give one example of alkali.

Ans: Alkalis are bases that are completely soluble in water or they are the water-
soluble hydroxides of metals.
Examples – Sodium Hydroxide (NaOH)

4. You are given a hammer, a battery, a bulb, wires, and a switch.

(a) How could you use them to distinguish between samples of metals and non-
metals?
Ans: To distinguish between metals and non-metals –
● With a hammer: Checking for malleability.
By beating the sample with a hammer we can find if the sample is a metal or non-
metal. Metals exhibit the property of malleability, where they can be beaten into thin
sheets, while non-metals being brittle, tend to break.
● With a battery, bulb, wires, and switch: Checking for conductivity.
Set up the circuit below.

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By placing the sample between terminals A and B, we can find if the sample is metal
or non-metal. Metals are good conductors of electricity, while non-metals are not. So
if by placing the sample between the terminals the bulb glows, it is a metal; if the bulb
does not glow, then it is a non-metal.

(b) Assess the usefulness of these tests to distinguish between metals and non-
metals.
Ans: These tests are useful in distinguishing between metals and non-metals:
● Beating the sample with a hammer, we can check for its malleability, i.e. checking
the physical property of the sample. Metals exhibit the property of malleability,
where they can be beaten into thin sheets, while non-metals being brittle, tend to
break.
● Using an electric circuit we can check for the conductivity of the sample to
determine whether it is a metal or a non-metal. Metals are good conductors of
electricity, while non-metals are not.

5. Name an alloy of
(i) Aluminium used in the construction of aircraft.
Ans: Duralumin is a strong, hard, lightweight alloy of aluminum that is widely used
in aircraft construction.
Composition of Duralumin – Al(95%),Cu(4%),Mg(0.5%),Mn(0.5%)

(ii) Lead used in joining metals for electric work.

Ans: Solder is an alloy of lead and tin that has a low melting point and is used for
welding electrical wires together.
Composition of Solder – Pb(50%),Sn(50%)

(iii) Copper used in household vessels.

Ans: Brass is an alloy of copper and zinc that is used for making household vessels.
Composition of Brass – Cu(80%), Zn(20%)

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6. What are the three important properties of aluminium which are responsible
for its great demand in the industry?
Ans:
a) Aluminium is a good conductor of electricity.
b) It is not attacked by water, i.e. it is resistant to corrosion.
c) It is a powerful reducing agent.
d) It is malleable and ductile.

7. Which of the following metals would give hydrogen when added to dilute HCl?
(1) Iron
(2) Copper
(3) Magnesium
Ans:
Iron and magnesium would liberate hydrogen gas on reacting with dilute HCl. These
are active metals that are placed above hydrogen in the activity series.
Reaction –

Fe  2HCl  FeCl2  H 2 

Mg  2HCl  MgCl2  H 2 

Since copper is placed below hydrogen in the activity series, it has lower reactivity
and will not evolve hydrogen gas when added to dilute HCl.
Reaction –
Cu  HCl  (No  reaction)

8. Define an alloy and an amalgam. State the main constituents of the following
alloys – Stainless steel, Bronze. In which property, each of them is different
from its main constituent?
Ans:

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● An alloy is a homogeneous mixture of two or more metals, or a metal and a
nonmetal. It is prepared by first melting the primary metal, and then, dissolving the
other elements in it in definite proportions. It is then cooled to room temperature.
Examples of Alloys – Brass is an alloy of copper and zinc (Cu and Zn), and bronze
is an alloy of copper and tin (Cu and Sn).
● An alloy, with one of the metals as mercury, is called amalgam.
An example of amalgam is the mixture of mercury with silver which is used to fill
dental cavities.
Main constituents of:
● Stainless steel – Stainless steel is an alloy of iron, chromium, carbon, and nickel. It
exhibits a higher level of resistance to corrosion by rust formation than compared
to its major constituent iron.
● Bronze – Bronze is an alloy of copper and tin (Cu and Sn). It has a lower electrical
conductivity than its constituents and is less malleable than copper.

9. A group of students looked at different metals and metal sulphate solutions

are given in a tabular form. From the data, answer the following:
Metal Metal sulphate solution Colour
1. Chromium Chromium sulphate Green
2. Cobalt Cobalt sulphate Pink
3. Copper Copper sulphate Blue
4. Magnesium Magnesium sulphate Colourless

(a) Which metal reacted with all other sulphate solutions?

Ans: Magnesium (Mg) reacted with all other sulphate solutions.

(b) Which metal did not react with any other metal sulphate solution?
Ans: Copper (Cu) did not react with any other metal sulphate solution.

(c) Arrange the metals in decreasing order of reactivity.

Ans: The decreasing order of reactivity of metals is Mg > Cr > Co > Cu.

Class X Science www.vedantu.com 23

10. Choose the appropriate element from the following:
(1) A metal that gets covered with a protective film of its oxide (Al, Cu, Ag).
Ans: Aluminium (Al)

(2) A metal that burns in air with golden flame (Zn, K, Na).
Ans: Sodium (Na)

(3) A metal that can displace hydrogen from boiling water as well as steam (K,
Zn, Fe).
Ans: Zinc (Zn)

11. Write one point of difference between electrolytic reduction and reduction
with carbon. Give one example of each.
Ans: In the case of electrolytic reduction, electrolysis is used for reduction, i.e. the
reduction takes place at the cathode by the gain of electrons during electrolysis.
Example –
NaCl(molten) 
electrolysis
 Na   Cl
Cathode  Na   e  Na(reduction)
While reduction with carbon, carbon acts as the reducing agent, i.e. reduction is
carried out by heating a metal oxide with coke.
Example –
ZnO  C(coke) 
heat
Zn  CO

12. Write the equation for the reaction of

(a) Iron with steam.
Ans: 3Fe(s)  4H2O(g)  Fe3O4 (s)  H2 (g)

Class X Science www.vedantu.com 24

(b) Calcium with water.
Ans: Ca(s)  2H2O(l)  Ca(OH)2 (aq)  H2 (g)

(c) Potassium with water.

Ans: 2K(s)  2H2O(l)  2KOH(aq)  H2 (g)  heat

13. Define the following terms:

(a) Minerals
Ans: Minerals – Minerals are substances that are formed naturally on Earth. They are
usually solid and inorganic with a crystal structure and are formed naturally by
geological processes. These are combined states of metals with other materials like
soil, sand, rocks, etc.

(b) Ores
Ans: Ores – Ores are minerals that have a higher concentration of a certain element.
A mineral can be considered as an ore when a metal can be extracted commercially
and profitably from that mineral.

(c) Gangue
Ans: Gangue – Gangue is the earthy impurities such as mud, sand, clay, rock, or any
other material that is associated with ores.

14. Pratyush took sulphur powder on a spatula and heated it. He collected the
gas evolved by inverting a test tube over it. What will be the action of gas in
–
(1) Dry litmus paper?
(2) Moist litmus paper?
Write a balanced chemical equation for the reaction taking place.
Ans:

Class X Science www.vedantu.com 25

Sulfur burns in oxygen with a blue flame to form sulfur dioxide SO2 , which has a
suffocating smell.
Balanced Chemical Equation – S(s)  O2 (g)  SO2 (g)

(1) SO2 with dry litmus paper – SO2 in its gaseous state does not change the color of
dry litmus.
(2) SO2 with moist litmus paper – SO2 turns moist blue litmus red, as it forms
sulphurous acid with water, which is acidic in nature.
Balanced Chemical Equation – SO2 (g)  H2O(aq)  H2SO3 (aq)

15. Write any three differences between metals and non-metals on the basis of
chemical properties?
Ans:
Metals Non-metals
They dissolve in mineral acids to form They generally do not react
salt and liberate some gas. with mineral acids.
They are good reducing agents. They are good oxidizing agents.
Their oxides are basic in nature. Their oxides are acidic in nature.
They usually form unstable hydrides. They usually form stable hydrides.
They displace hydrogen from They do not react with water (or steam).
water (or steam).

16. Why is titanium metal called strategic metal? Mention two of its properties
that make it so special.
Ans: Titanium metal is called strategic metal because it is used in the production of
spacecraft, aircraft and missiles, and other war equipment.
Properties that make titanium special are:
(i) It is light in weight but at the same time stronger than the other metals.
(ii) It is not affected by corrosion even after being exposed to the atmosphere for a
long duration.

Class X Science www.vedantu.com 26

17.
(a) What is corrosion?
Ans: Corrosion is the process that causes damage to the metal, due to the eating up of
the surface of the metal when kept exposed to air and moisture for a long time. It is a
natural process that results in the transformation of pure metals into undesirable
substances when they react with air and water.

(b) How is corrosion caused?

Ans: Corrosion is mainly caused by a chemical or electrochemical reaction of the
metal with its environment that results in its gradual destruction. It converts the metal
into a more chemically stable oxide or hydroxide or sulphide.
Example – Copper metal reacts with moist carbon dioxide in the air and results in the
formation of a green coat of copper carbonate over the metal surface.
2Cu  H 2O  CO2  O2  Cu(OH) 2 .CuCO3
Reaction –
Copper  AtmosphericGases  CopperCarbonate(green)

3
(c) Complete the reaction – 2Fe  O 2  xH 2O 
2
3
Ans: 2Fe  O 2  xH 2O  Fe 2O3.xH 2O
2
Here, Fe2O3.xH2O is hydrated ferric oxide, i.e. rust.

18.
(1) Choose metal from the reactivity series which will not react with steam.
Ans: Gold (Au)

(2) Choose one metal that will safely react with dilute sulphuric acid.
Ans: Zinc (Zn)

Class X Science www.vedantu.com 27

(3) Name the salt formed when metal chosen in (2) reacts with sulphuric acid.
Ans: The salt formed is zinc sulphate ZnSO4 and it is colorless.

19. A copper plate was dipped into a solution of AgNO3 . After some time a black
layer was deposited on the copper plate. State the reason for it. Write the
chemical equation for the reaction involved.
Ans: When a copper plate is dipped in a solution of silver nitrate AgNO3 , a black
layer of silver will be deposited over the copper plate. This is because copper is above
silver in the activity series, meaning copper is more reactive than silver. Thus, a
displacement reaction occurs between copper (more reactive) and silver (less
reactive), that copper displaces silver from its solution AgNO3 and forms copper
nitrate Cu(NO3 )2 . This results in the deposition of silver over the plate that can be
seen as a black layer.
Reaction – Cu(s)  2AgNO3 (aq)  Cu(NO3 )2 (aq)  2Ag(s)

20. Give an example of metal which

(i) is a liquid at room temperature.
Ans: Mercury

(ii) can be easily cut with a knife.

Ans: Sodium

(iii) is the best conductor of heat.

Ans: Silver

(iv) is a poor conductor of heat.

Ans: Lead

21. Explain the meaning of malleable and ductile.

Class X Science www.vedantu.com 28
Ans:
● Malleable – The ability of metals to be beaten into thin sheets is called malleability.
Example: Iron, Copper.
● Ductile – The ability of metals to be drawn into thin wires is called ductility.
Example: Gold, Silver.

22.
(i) Write the electron-dot structures for sodium, oxygen, and magnesium.

(ii) Show the formation of Na2O and MgO by the transfer of electrons.

(iii) What are the ions present in these compounds?

Ans:

(iii) Ions present in Na 2O are Na  and O 2

Ions present in MgO are Mg 2 and O 2

Class X Science www.vedantu.com 29

23. Metallic oxides of zinc, magnesium, and copper were heated with the
following metals:
Metal Zinc Magnesium Copper
Zinc oxide
Magnesium oxide
Copper oxide

In which case will you find displacement reactions taking place?

Ans: Based on the activity series of metals, the displacement reactions will take place
as below:
Metal Zinc Magnesium Copper
Zinc oxide No reaction Displacement No reaction
Magnesium oxide No reaction No reaction No reaction
Copper oxide Displacement Displacement No reaction

24. You must have seen tarnished copper vessels being cleaned with lemon or
tamarind juice. Explain why these sour substances are effective in cleaning
the vessels.
Ans: Copper metal reacts with moist carbon dioxide in the air and results in the
formation of a green coat of copper carbonate over the metal surface. Thus it loses its
shiny brown appearance.
2Cu  H 2O  CO2  O2  Cu(OH) 2 .CuCO3
Reaction –
Copper  AtmosphericGases  CopperCarbonate(green)

To remove the green layer of copper carbonate, lemon juice or tamarind juice is used.
The citric acid and/or tartaric acid present in these juices dissolves the copper
carbonate and converts it into soluble copper citrate or copper tartrate, which can be
easily removed from the surface and hence restoring the shiny brown appearance of
copper.

25. A man went door to door posing as a goldsmith. He promised to bring back
the glitter of the old and dull ornaments. An unsuspecting lady gave a set of
gold bangles to him which he dipped in a particular solution. The bangles
sparkled like new but their weight was reduced drastically. The lady was

Class X Science www.vedantu.com 30

 upset but after a futile argument, the man beat a hasty retreat. Can you play
the detective to find out the nature of the solution he had used?
Ans: The man used the Aqua-regia solution, which is a 3:1 ratio mixture of
concentrated hydrochloric acid and concentrated nitric acid. This solution has the
ability to dissolve gold. Thus, when the man dipped the gold bangles in this solution,
it had dissolved a significant amount of gold from the bangles, which explains the
drastic loss in weight of the bangles. But by dissolving the outer layer, the inner shiny
layer appears that gives off the appearance that the bangles were cleaned.

26. Differentiate between metal and non-metal on the basis of their chemical
properties.
Ans:
Metals Non-metals
They dissolve in mineral acids to They generally do not react
form salt and liberate some gas. with mineral acids.
They are good reducing agents. They are good oxidizing agents.
Their oxides are basic in nature. Their oxides are acidic in nature.
They usually form unstable hydrides. They usually form stable hydrides.
They displace hydrogen from water They do not react with water (or steam).
(or steam).

27. An element reacts with oxygen to form an oxide which dissolves in dilute
hydrochloric acid. The oxide formed also turns a solution of red litmus blue.
Is the element metal or non-metal? Explain with the help of a suitable
example.
Ans: The element is metal because the oxides of metals are basic in nature, which can
turn red litmus solution blue. Also since the oxide seems to have dissolved in dilute
hydrochloric acid, this also suggests that the oxide is basic.
Since metallic oxides are typically basic in nature, we can conclude that the element
is a metal.
Example – Consider the metal to be Magnesium.
Reactions –
With oxygen to form an oxide: 2Mg(s)  O2 (g)  2MgO(s)

Class X Science www.vedantu.com 31

Oxide dissolving in hydrochloric acid: MgO(s)  2HCl(aq)  MgCl2 (aq)  H2O(l)

In aqueous conditions, it forms a base that turns red litmus blue:

MgO(s)  H2O(l)  Mg(OH)2

28. Nikita took Zn, Al, Cu, Fe, Mg, and Na metals, and put each metal in cold
water and then hot water. She then reacted the metal with steam.
(i) Name the metal which reacts with cold water.
Ans: Na

(ii) Which of the above metals react with steam?

Ans: Zn, Al, Fe

(iii) Name the metal which reacts with hot water

Ans: Mg

(iv) Arrange these metals in order of increasing reactivity

Ans: Na > Mg > Al > Zn > Fe > Cu

29. A student was given Mg, Zn, Fe, and Cu metals. He put each of them in dilute
HCl contained in different test tubes. Identify which of them
(i) will not displace H 2 from dilute HCl.

Ans: Cu, because it is less reactive than hydrogen in the activity series.

(ii) forms a pale green substance.

Ans: Fe, because it forms ferrous chloride in hydrochloric acid.

(iii) will give H 2 with 5% HNO3 .

Ans: Mg gives off hydrogen gas upon reacting with nitric acid.

Class X Science www.vedantu.com 32

(iv) will be displaced from its salt solution by all other metals.
Ans: Cu, because it has lower activity than compared to the other three metals.

30. A metal ‘X’ is found in the form of filings which burns vigorously when
sprinkled on flame. When these filings are treated with sulphur, a black
colored compound ‘Y’ is formed which is not attracted by a magnet. ‘X’
reacts with dilute HCl to liberate hydrogen gas. ‘X’ reacts with steam to form
‘Z’ along with hydrogen gas. Identify ‘X’, ‘Y’, and ‘Z’. Write the reactions
involved.
Ans: We can say that X is a metal that can react with steam and with hydrochloric
acid to liberate hydrogen gas. Since ‘X’ is magnetic but its sulphide is non-magnetic,
we can say that ‘X’ is iron and ‘Y’ is iron sulphide.
When iron reacts with steam it forms ‘Z’, which is iron (ii, iii) oxide.
Reactions –
Iron filings with sulphur: Fe  S  FeS
Iron filings with hydrochloric acid: Fe  2HCl  FeCl2  H2

Iron filings with steam: 3Fe  4H2O  Fe3O4  4H2

Thus – X is Fe , Y is FeS and Z is Fe3O4 .

Long Answer Questions 5 Marks

1.
(a) Name a metal that does not stick to glass?
Ans: Mercury

(b) Name a non-metal which is a good conductor of electricity?

Ans: Graphite

(c) Name the metal which is commonly used in thermit welding?

Class X Science www.vedantu.com 33

Ans: Aluminum

(d) What gets deposited at the cathode, a pure or impure metal?

Ans: A pure metal is always deposited at the cathode

(e) What is the nature of Zinc oxide?

Ans: Zinc oxide (ZnO) is an amphoteric oxide.

2. Name three common forms in which metals occur in nature. Explain the
interaction between metals and dilute acid?
Ans: The three common forms in which metals occur in nature are:
● Sulphide form – e.g. copper pyrite (CuFeS2 )

● Oxide form – e.g. Bauxite (Al2O3 .2H2O)

● Carbonate form – e.g. Calamine (ZnCO3 )

Active metals generally interact with dilute hydrochloric acid or dilute sulphuric acid
and liberate hydrogen gas. Also, those metals that are below hydrogen in the activity
series neither liberate hydrogen gas nor react with the dilute acid.
Example reactions of metals with dilute hydrochloric acid –

Fe  2HCl  FeCl2  H 2 

Mg  2HCl  MgCl2  H 2 

3. Sample pieces of five metals A, B, C, D, and E were added to the tabulated

solutions separately. The results observed are shown in the table:
Metal FeSO4 CuSO4 ZnSO4 AgNO3 Al 2 (SO4 )3
No Coating
A No Change No Change No Change
Change On metal
Grey Deposit Brown coating No Coating
B No Change
on metal on metal Change on metal
C No Change No Change No No No Change

Class X Science www.vedantu.com 34

 Change Change
No Coating
D No Change --- No Change
Change on metal
New New
E --- Brown coating No Change
coating coating

Based on the observations recorded in the table, answer the following:

(1) Which is the most reactive metal?
Ans: E is the most reactive because it displaces almost all of the elements from their
solutions

(2) Which is the least reactive metal?

Ans: C is the least reactive because it does not react with any of the solutions to
undergo displacement.

(3) What would be observed if metal D were added to a solution of copper (II)
sulphate?
Ans: It is clear that D is more reactive than silver but less reactive than iron. Thus it
can displace copper from CuSO4

(4) What would be observed if metal E were added to a solution of iron (II)
sulphate?
Ans: Metal E is more reactive than zinc because it can displace zinc from its solution.
Since iron is less reactive than zinc, we can conclude that E would displace iron from
FeSO4

(5) Arrange the metals A, B, C, D, and E in decreasing order to their reactivity?

Ans: The decreasing order of reactivity – E > B > D > A > C.

4. Hydrogen gas is evolved by reacting a piece of magnesium ribbon with water:

(1) Describe how it could be shown that the gas collected is hydrogen.

Class X Science www.vedantu.com 35

Ans: If a lighted splint is brought near the collected gas, it will burn very brightly,
along with a ‘pop’ sound. This shows that the gas evolved by a magnesium ribbon
upon its reaction with water is hydrogen.

(2) Write a chemical equation for the reaction taking place between magnesium
and water using symbols.
Ans: The chemical equation for the reaction is:
Mg(s)  2H 2O(l)  Mg(OH) 2 (aq)  H 2 (g) 

(3) Suggest how the appearance of magnesium would change after a week.
Ans: After a week’s time, magnesium will lose all its shine and a deposit of
magnesium hydroxide will be formed on the surface of the metal.

(4) A few drops of universal indicator solution were added to water in the
beaker. What colour would expect to see and what pH would this colour
indicate?
Ans: The indicator will become blue, indicating that the solution is basic. The pH of
the solution would be more than seven.

5. Samples of four metals A, B, C, and D were taken and added to the following
solution one by one. The results obtained have been tabulated as follows:
Metal FeSO4 CuSO4 ZnSO4 AgNO3
A No reaction Displacement --- ---
B Displacement --- No reaction ---
C No reaction No reaction No reaction Displacement
D No reaction No reaction No reaction No reaction

Use the table given above to answer the following questions about metals A, B,
C, and D.
(i) Which is the most reactive metal?
Ans: B is the most reactive metal because it displaces the iron from its solution, which
is the most reactive of all the elements.

Class X Science www.vedantu.com 36

(ii) What would you observe if B is added to a solution of Copper(II) sulphate?
Ans: It is clear that B is more reactive than iron, and since copper is less reactive than
iron, B can displace copper from CuSO4 .

(iii) Arrange the metals A, B, C, and D in order of decreasing reactivity.

Ans: The decreasing order of reactivity is B > A > C > D.
6. Give reasons:
(a) Platinum, gold, and silver are used to make jewelry.
Ans: Platinum, gold, and silver are used to make jewelry due to their low reactivity.
These metals are placed at the bottom of the activity series and are also called noble
metals. They do not corrode when exposed to air, water, or chemicals. Thus they do
not lose their shine and have a bright luster, which makes them suitable for making
jewelry. These metals are also highly malleable and ductile, so they can be shaped
and designed as required.

(b) Sodium, potassium, and lithium are stored under oil.

Ans: Sodium, potassium, and lithium are highly reactive in nature. They can react
vigorously with both air and water and burn. So they are kept immersed in oil to avoid
contact with air and water.

(c) Aluminum is a highly reactive metal, yet it is used to make utensils for
cooking.
Ans: Aluminium, despite being a highly reactive metal is typically used to make
cooking utensils because the corrosion of aluminium has an advantage. When
aluminium corrodes, it forms a layer of aluminium oxide (Al2O3 ) over the metal. This
oxide layer deposited on its surface acts as a protective coating and prevents further
corrosion of the metal from the attacks of water, air, acids or alkalis, or even from
heat. Also, aluminium is a good conductor of heat, which helps in the cooking process.
It is easily available, malleable, and ductile as well. These factors make it suitable for
cooking utensils.

(d) Carbonate and sulphide ores are usually converted into oxides during the
process of extraction.

Class X Science www.vedantu.com 37

Ans: Carbonate and sulphide ores are usually converted into oxides during the process
of extraction because it is easier to extract the metal from its oxide than compared to
carbonates and sulphides. This is also economically feasible and profitable.

7. Four metals A, B, C, and D are, in turn, added to the following solutions one
by one. The observations made are tabulated below:
Metal FeSO4 CuSO4 ZnSO4 AgNO3
A No reaction Displacement --- ---
B Displacement --- No reaction ---
C No reaction No reaction No reaction Displacement
D No reaction No reaction No reaction No reaction

Answer the following questions based on the above information.

(i) Which is the most active metal and why?
Ans: B is the most reactive metal because it displaces the iron from its solution, which
is the most reactive of all the elements.

(ii) What would be observed if B is added to a solution of copper (II) sulphate

and Why?
Ans: It is clear that B is more reactive than iron, and since copper is less reactive than
iron, B can displace copper from CuSO4 .

(iii) Arrange the metals A, B, C, and D in order of increasing reactivity.

Ans: The decreasing order of reactivity is B > A > C > D.

(iv) Container of which metal can be used to store both zinc sulphate solution
and silver nitrate solution.
Ans: Metal D can be used to make containers because out of all four elements, it is
the least reactive. Also, it shows no displacement reactions with both zinc sulphate
solution and silver nitrate solution.

Class X Science www.vedantu.com 38

(v) Which of the above solutions can be easily stored in a container made up of
any of these metals?
Ans: Zinc sulphate can be easily stored in a container made up of any of these metals,
because it shows no reaction with these metals.

Class X Science www.vedantu.com 39

 Chap 3 : Metals and Non-Metals www.cbse.online

File Revision Date : 10 July 2019

CBSE Previous Years Chapterwise Questions Exam 2019-2020
CLASS : 10th
CHAPTER 3
SUB : Science
For more subject
visit www.cbse.online or whatsapp at 8905629969

Metals and Non-Metals

ONE MARK QUESTIONS room temperature.

Ans : [CBSE 2013]
Mercury is a metal and Bromine is a non-metal present
1. Give one most suitable word for the following as a liquid at room temperature.
statements:
a. Metal oxides which show basic as well as acidic 10. Name two metals which react with dilute HNO3 to
behaviour. evolve H2 gas.
b. Iodine, a shining non-metal. Ans : [CBSE 2013]
Ans : [CBSE 2015] Mn and Mg.
a. Amphoteric oxides.
b. Lustrous. 11. What is formed when sodium absorb moisture from
air? Give equation also.
2. Write the chemical equation for the reaction taking Ans : [CBSE 2013]
place when steam is passed over hot Aluminium?
Sodium hydroxide and hydrogen gas is formed:
Ans : [CBSE 2015] 2Na(s) + 2H2O(l) $ 2NaOH(aq) + H2(g)
Heat
2Al(s) + 3H2O(aq) Al2O3(S) + 3H2(g)
12. Why sulphide and carbonate ores are converted into
3. What happens when carbon dioxide is compressed in oxides?
water at high pressure? Ans : [CBSE 2013]
Ans : [CBSE 2015] It is because oxides are more easier to be reduced than
CO2 + H2O $ H2CO3 sulphides and carbonates.
Carbonic acid is formed.
NO NEED TO PURCHASE ANY BOOKS
4. Why oxides of highly reactive metals cannot be For session 2019-2020 free pdf will be available at
reduced by carbon? www.cbse.online for
Ans : [CBSE 2015] 1. Previous 15 Years Exams Chapter-wise Question
It is because highly reactive metals themselves are Bank
good reducing agents, so they can’t be reduced by 2. Previous Ten Years Exam Paper (Paper-wise).
carbon. 3. 20 Model Paper (All Solved).
4. NCERT Solutions
5. Give reason why: Electric wires are coated with plastic. All material will be solved and free pdf. It will be
Ans : [CBSE 2015, 2014] provided by 30 September and will be updated regularly.
Disclaimer : www.cbse.online is not affiliated to Central Board of Secondary Education,
New Delhi in any manner. www.cbse.online is a private organization which provide free
Plastic is a non-conductor of electricity, therefore study material pdfs to students. At www.cbse.online CBSE stands for Canny Books
For School Education
electric wires are coated with plastic.

6. Give composition of the alloy: brass and bronze.

13. From amongst the metal, sodium, calcium, aluminium,
Ans : [CBSE 2014]
copper and magnesium, name the metal:
Brass is made up of Cu and Zn. Bronze is made up of a. which reacts with water only on boiling.
Cu and Sn. b. another one which does not react even with steam.
7. What is the formula of rust? Ans : [CBSE 2013]
Ans : [CBSE 2014] a. Mg,
b. Cu
Rust is hydrated ferric oxide, Fe 2 O 3 $ xH 2 O .
14. Name any one metal which reacts neither with cold
8. An alloy has low melting point and is therefore water nor with hot water but reacts with heated
used for electrical fuse. Name the alloy and write its steam to produce hydrogen gas.
constituents.
Ans : [CBSE 2013]
Ans : [CBSE 2014]
Iron (Fe) :
Solder is an alloy. It is made up lead and tin. Heat
3Fe(s) + 4H2O(g) Fe3O4(s) + 4H2(g)
9. Name one metal and one non-metal in liquid state at

Download all GUIDE and Sample Paper pdfs from www.cbse.online or www.rava.org.in Page 23
Chap 3 : Metals and Non-Metals www.cbse.online

15. Name the metals Which have low melting point. 4Al(s) + 3O2(g)
Heat
2Al2O3(S)
Aluminium oxide
Ans : [CBSE 2012, 2011]
Gallium and Caesium. 26. A non-metal X exists in two different forms V and Z.
Y is the hardest known natural substance, whereas Z
16. Name a non-metal which is lustrous whereas a metal is a good conductor of electricity. Identify X, Y and Z.
which is non-lustrous.
Ans : [CBSE 2011]
Ans : [CBSE 2012, 2011]
X is Carbon, Y is Diamond, Z is Graphite.
Iodine is a lustrous non-metal, Lead is a non-lustrous
metal. 27. Why does calcium float in water?
Ans : [CBSE 2011]
17. Choose the amphoteric oxide amongst the following:
Na2O, ZnO, Al2O3, CO2, H2O Calcium form hydrogen gas on reaction with water,
Ans : [CBSE 2012] bubbles of hydrogen gas sticks to the calcium metal
and that is why calcium floats in water.
ZnO and Al2O3 are amphoteric oxides. Ca(s) + 2H2O(l) $ Ca(OH)2(aq) + H2(g)
18. A green layer is gradually formed on copper plate 28. Which gas is liberated when a metal reacts with an
when left exposed to air for a week in a bathroom. acid? How will you test this gas?
What could this green substance be?
Ans : [CBSE 20111
Ans : [CBSE 2012]
Hydrogen gas is formed.
CuCO3.Cu(OH)2, Basic copper carbonate. Bring a burning splinter near the gas, it will burn with
‘pop’ sound.
19. Why do ionic compounds have high melting point?
Ans : [CBSE 2012] 29. An element ‘A’ form two oxides AO and AO2. The
It is due to strong forces of attraction between oxide AO is neutral whereas the oxide AO2 is acidic
positively charged and negatively charged ions. in nature. Would you call element ‘A’ a metal or a
non-metal?
20. Define metallurgy. Ans : [CBSE 2011]
Ans : [CBSE 2012] The element is carbon which is a non- metal. CO is
Metallurgy. All the processes involved in the extraction neutral and CO2 is acidic in nature.
of metals from its ore is called metallurgy.
30. Why do silver ornaments lose their shine when kept in
21. What kind of compounds are called Ionic compounds? open air for sometime?
Ans : [CBSE 2012] Ans : [CBSE 2011]
Those compounds which are formed between metals It is because Ag reacts with H2S present in the
and non-metals by transfer of electrons e.g., NaCl, atmosphere to form Ag2S due to which it loses its
KCl etc. shine.

22. How are ionic compounds formed? 31. Why do we use copper and aluminium wire for
Ans : [CBSE 2012] transmission of electric current?
Ans : [CBSE 2011]
Gallium has a melting point 303 K, it melts on palm.
Copper and aluminium are ductile and good
23. It nature, aluminium is found in combined state conductors of electricity, therefore they are used in
whereas silver/gold are found in free state. Give transmission wires.
reason.
Ans : [CBSE 2012, 2010, 2011] 32. Why do we use copper and aluminium wire for the
transmission of electric current?
Aluminium is reactive metal, therefore it is found in
Ans : [CBSE 2011]
combined state whereas silver/gold are less reactive
(noble) metals and so are found in free state. It is has 4 to 8 valence electrons, it is a non-metal.
Exception is hydrogen which has 1 valence electron
24. Why do ionic compounds conduct electricity in molten and He which has 2 valence electrons, but these are
state and not in solid state? non- metals.
Ans : [CBSE 2010,2012]
33. Name two metals which are found in nature in free
Ionic compounds do not conduct electricity in solid state.
state because ions are not free to move. In molten
Ans : [CBSE 2011]
state, ions are free to move.
Gold and silver are found in free state.
25. Write a balanced chemical equation for the reaction:
Aluminium when heated in air. Write the name of the 34. Why do we apply paint on iron grills?
product formed. Ans : [CBSE 2011]
Ans : [CBSE 2012] Iron grills are painted to prevent them from rusting.

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Chap 3 : Metals and Non-Metals www.cbse.online

35. Why does stainless steel not get rusted easily? c. Which is used to galvanise iron articles?
Ans : [CBSE 2010] d. Whose articles when exposed to air forms a black
coating?
Stainless steel is an alloy of Fe, C, Cr and Ni, therefore
it does not get rusted. Ans : [CBSE 2016]
a. Carbon makes it hard and strong. Tungsten also
36. Why do we use gold and platinum metals in jewellery? makes it hard and strong.
Ans : [CBSE 2010] b. Mercury is alloyed with metals to form amalgam.
Gold and Platinum are lustrous metals and do hot c. Zinc metal is used for coating over iron metal to
react with substances present in the atmosphere, galvanise iron.
therefore remain lustrous for a long time. d. Silver articles acquire black coating when left
exposed to the atmosphere.
37. Which property makes solder alloy suitable for welding
electric wires? 45. Which of the following listed metals can displace zinc
from its salt solution? Give reason for your answer
Ans : [CBSE 2010]
with a chemical equation:
Its melting point is low which makes solder suitable Copper, Lead, Magnesium, Silver
for welding. Ans : [CBSE 2016]
38. What is the valency of silicon with atomic number 14? Magnesium can displace zinc from zinc salt solution
Ans : [CBSE 2010] because Mg is more reactive than zinc:
Mg(s) + ZnSO4(aq) $ MgSO4(aq) + Zn(s)
Si (2,8,4): Its valency is 4 because it can share four
electrons to become stable. 46. The reaction of metal X with Fe2O3 is highly exothermic
and is used to join railway tracks. Identify metal X.
39. What is the valency of phosphorus with atomic
Write the chemical equation for the reaction.
number 15?
Ans : [CBSE 2016]
Ans : [CBSE 2010]
X is Al.
P (2, 8, 5): Its valency is 3 because it can gain three 2Al + Fe2O3 $ Al2O3 + 2Fe
electrons to become stable.
47. (a) In electrolytic refining of impure copper metal,
40. What is the valency of an element with atomic number
what are used as cathode and anode?
35? (b) Show the formation of HgCl2 from magnesium
Ans : [CBSE 2010] and chlorine atoms.
Br(35) (2, 8, 18, 7): Its valency is equal to 1 because Ans : [CBSE 2016]
it can gain one electron to become stable. (a) Pure copper is used as the cathode, impure copper
41. Arrange the following metals in decreasing order of is used as the anode.
reactivity are Na, K, Cu, Ag
(b)
Ans : [CBSE 2009]
K > Na > Cu > Ag is the decreasing order of reactivity. 48. Write one example of each of
a. a metal which is so soft, that it can be cut with a
42. Which of the following two metals will melt at body
knife and a non-metal which is the hardest known
temperature (37°C): Gallium, Magnesium, Caesium,
substance.
Aluminium?
b. a metal and a non-metal which exist as liquid at
Ans : [CBSE 2008(C)] room temperature.
Gallium and Caesium will melt at the body Ans : [CBSE 2015]
temperature.
a. Sodium is so soft that it can be easily cut with a
43. Show the electronic transfer in formation of MgCl2 knife.
from its elements. b. Diamond is the allotrope of carbon, which is the
Ans : [CBSE 2008] hardest known substance and a non-metal.
c. Mercury is a metal and Bromine is a non-
metal which are found in liquid state at room
temperature.

49. Mention the name of metals for the following:

a. Two metals which are alloyed with iron to make
TWO MARKS QUESTIONS stainless steel.
b. Two metals which are used to make jewellery.
Ans : [CBSE 2015]
44. Name a metal/non-metal
a. Which makes iron hard and strong? a. Nickel and chromium.
b. Which is alloyed with other metal to make b. Gold and platinum
amalgam?
50. Why is sodium chloride soluble in water but not in
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Chap 3 : Metals and Non-Metals www.cbse.online

kerosene? b. Electrical wires are made up of copper.

Ans : [CBSE 2015] Ans : [CBSE 2014,2013]
Sodium chloride is the ionic compound and it form a. Metals are sonorous i.e., produce sound when
ions in water, therefore it is soluble in water whereas struck with a hard substance.
kerosene is a non-polar covalent compound, NaCl does b. Copper is a good conductor of electricity and is
not form ions in kerosene, therefore, it is insoluble in highly ductile.
it.
56. Out of the two metals P and Q, P is less reactive than
51. a. Why do aluminium sheets not corrode easily? Q. Suggest an activity to arrange these metals in the
b. Why is copper vessel corroded with a green order of decreasing reactivity. Support your answer
coating in rainy season? with a suitable chemical equation.
Ans : [CBSE 2015] Ans : [CBSE 2014]
a. Aluminium sheets are covered with an oxide layer Add Q in the salt solution of P. If Q is able to displace
which makes it passive. P’ from its salt solution, then it shows P is less reactive
b. It is due to the formation of basic copper than Q
carbonate, CuCO3.Cu(OH)2. Q + PR $ QR + P

52. A copper plate was dipped into a solution of silver 57. Define alloy. How an is alloy prepared?
nitrate. After sometime a black layer was observed on Ans : [CBSE 2014]
the surface of copper plate. State the reason for it and
Alloy is an homogeneous mixture of two or more
write chemical equation for the reaction involved.
metals. One of them can be a non-metal also. Alloys
Ans : [CBSE 2015] are made by melting two metals together and then
Copper is more reactive than Ag, therefore it can cooling it.
displace Ag from AgNO3 solution:
Cu(s) + 2AgNO3(aq) $ Cu(NO3)2(aq) + 2Ag(s) 58. In one of the methods of rust prevention, iron is not
coated with anything. Name that method and define
53. Give reason: it.
a. Carbonate and sulphide ores are usually converted Ans : [CBSE 2014]
into oxides during the process of extraction of
The method is alloy formation, by adding a suitable
metals.
metal or a non-metal.
b. Ionic compounds generally have high melting
point. Alloy is. a homogeneous mixture of two or more
c. Hydrogen is not a metal but has been assigned a metals. One of them can be a non- metal also. This
place in the reactivity services of metals. process is called alloying.
d. The galvanised iron article is protected against
rusting even if the zinc layer is broken. 59. Give reasons for the following:
a. Platinum, gold and silver are used for making
Ans : [CBSE 2015]
jewellery.
a. It is easier to reduce an oxide than sulphide and b. Sodium, potassium and lithium are stored under
carbonate ores. kerosene oil.
b. It is due to strong forces of attraction between c. Aluminium is highly reactive metal but still used
positive and negative ions. for making cooking utensils.
c. Hydrogen form H+ ions like metals, therefore it is d. Carbonate and sulphide ores are usually converted
included in the activity series. into oxides during the process of extraction.
d. Zinc is more reactive than iron, therefore it will Ans : [CBSE 2013, 2014]
get easily oxidised in preference to Fe and hence
protect iron from rusting even if zinc coating is a. It is because they are lustrous metals.
broken. b. These are highly reactive metals.
c. It forms an oxide layer on its surface which makes
54. A compound Z is formed by transfer of electrons from it passive.
the metal X to a non-metal Y, Identify the type of d. It is easier to reduce a metal oxide than sulphides
bond formed in the compound. List three properties and carbonates.
of compound formed by such type of bonds.
60. What happens to potassium and sodium if they are
Ans : [CBSE 2014]
kept in open? Why are they 3 immersed in kerosene
The bond formed is ionic bond: oil?
a. The compound will have high melting and boiling Ans : [CBSE 2013]
point.
b. It will be soluble in water. Potassium and Sodium if kept in open, can catch the
c. It will conduct electricity in molten state as well presence of moisture.
as in aqueous solution. They are immersed in kerosene so that they do
not react with air and H2O present in the atmosphere.
55. Give reason for the following:
a. School bells are made up of metals. 61. Why hydrogen gas is not evolved when a metal reacts

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Chap 3 : Metals and Non-Metals www.cbse.online

with nitric acid? Molecular weight of NaOH = 40 g mol-1. Y is NaOH

Ans : [CBSE 2013] and Z is H2 gas which easily catches fire.
Nitric acid is an oxidising agent, therefore H2(g) is not 68. Name the following:
evolved on reaction with metal. Dilute HNO3 mostly a. A metal which is preserved in kerosene.
gets reduced to NO in this process. b. A lustrous coloured non-metal.
c. A metal which melts when kept on palm.
62. Why is iron galvanised with zinc? Can it be galvanised
d. A metal which is a poor conductor of heat.
with copper? If not, why?
Ans : [CBSE 2013, 2012]
Ans : [CBSE 2013]
a. Sodium or Potassium
Iron is galvanised by zinc because zinc is more reactive
b. Iodine
than Fe. Iron cannot be galvanised by copper because
c. Gallium
copper is less reactive than iron and therefore iron
d. Lead
itself gets corroded when coated with copper.
69. Define the term alloy. Write the constituents of
63. Differentiate between roasting and calcination giving
Bronze.
examples.
Ans : [CBSE 2013]
Ans : [CBSE 2013]
Alloy is a homogeneous mixture of two or more metals.
Roasting Calcination One of them can be a non- metal also.

1. It is done in the It is done in the Alloys are made by melting two metals together
presence of oxygen. absence of oxygen. and then cooling it.

2. It is done with It is done with 70. Why do silver articles turn black and copper items
sulphide ores eg. carbonate ores e.g. turn green after sometime?
2ZnS + 3O 2 $ 2ZnO + 2SO 2 FeCO 3 Heat
FeO (s) + CO 2 (g) Ans : [CBSE 2013]
Silver turns black due to the formation of Ag2S, (Silver
sulphide). Copper turns green due to formation of
64. Name the ore of mercury. How mercury is extracted basic copper carbonate.
from its ore?
Ans : [CBSE 2013] 71. Give reasons for the following:
a. Iron grills are frequently painted.
Cinnabar (HgS) is the ore of mercury.
b. Gold ornaments retain their lustre even after
Roasting:
several years of use.
HgS(s) + O2(g) $ 2Hg(l) + SO2(g)
Cinnabar, on roasting gives Mercury and sulphur Ans : [CBSE 2013]
dioxide. Mercury can be purified by distillation a. It is done to prevent them from rusting.
process. b. Gold is least reactive, therefore it remains lustrous
even after several years.
65. How is copper obtained from Cu2S? Give reactions.
Ans : [CBSE 2013] 72. Give reasons for the following:
a. Aluminium oxide is considered has amphoteric
a. Roasting:
oxide.
Cu2S(s) + 3O2(g) $ 2Cu2O(s) + SO2(g)
b. Ionic compounds conduct electricity in molten
b. Self-Reduction:
Heat state.
Cu2S(s) + 2Cu2O(s) 6Cu(s) + SO2(g)
Ans : [CBSE 2012]
66. Explain, why calcium metal after reacting with water a. Al2O3 reacts with acids as well as bases, therefore
starts floating on its surface. Write the chemical it is regarded as amphoteric oxide.
equation for the reaction. b. In molten state, ions are free to move, therefore it
Ans : [CBSE 2013, 2012] conducts electricity.
Calcium reacts with water to form Ca(OH)2 and H2
73. How do properties of iron change when
gas.
a. a small quantity of carbon is mixed in it?
Ca(s) + 2H2O(l) $ Ca(OH)2(aq) + H2(g)
b. nickel and chromium are mixed in it?
The bubbles of hydrogen gas sticks to the surface of
calcium and therefore it floats over water. Ans : [CBSE 2012]
a. It becomes hard and does not get rusted.
67. When a metal X is reacted with cold water, it gives b. It becomes lustrous and malleable and so it does
a basic compound Y with molecular formula XOH not get rusted.
(Molecular mass 40) and liberates a gas Z which easily
catches fire. Identify X, Y, Z. 74. You must have seen tarnished copper vessels being
Ans : [CBSE 2013, 2012] cleaned with lemon or tamarind juice. Explain why
these sour substances are effective in cleaning the
X is Na (Sodium).
vessels.
2Na(s) + 2H2O(l) $ 2NaOH(aq) + H2(s)
(Cold) Ans : [CBSE 2012]

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Chap 3 : Metals and Non-Metals www.cbse.online

Copper vessel coated with a green layer of CuCO3. and then cooling the mould of two metals being mixed
Cu(OH)2 which reacts with acid present in lemon or that forms the alloy.
tamarind juice and get removed it. Some substances Solder is an alloy of lead and tin. It has low melting
contain acids which react with basic substances to point, therefore it is used for welding purposes.
form soluble salt which can be easily removed.
82. Using the electronic configuration, explain how
75. Name two metals which can be used to reduce metal magnesium atom combines with oxygen atom to form
oxides to metals. magnesium oxide by transfer of electrons.
Ans : [CBSE 2012] Ans : [CBSE 2011]
Aluminium and Magnesium
2Al + Fe2O3 $ Al2O3 + 2Fe
3Mg + Fe2O3 $ 3MgO + 2Fe

76. Write four important purposes of making alloys.

Ans : [CBSE 2011]
a. It is done to increase the hardness of the substance.
83. Write chemical equations that shows aluminium oxide
b. It is done so as to increase the resistance towards
corrosion. reacts with acid as well base.
c. It helps to modify reactivity. Ans : [CBSE 2011]
d. It lowers the melting point. Al2O3 + 2NaOH $ 2NaAlO2 + H2O
Al2O3 + 3H2SO4 $ Al2(SO4)3 + 3H2O
77. State four general properties of ionic compounds.
Ans : [CBSE 2011] 84. Why is carbon not used for reducing aluminium oxide
a. They are soluble in water. to obtain Al?
[CBSE 2010]
b. They are hard but brittle solids.
or
c. They conduct electricity in solid state and in their
Metals placed high in reactivity series cannot be
aqueous solution.
obtained from their compounds by heating with
d. They have high melting and boiling points.
carbon?
78. The way, metals like sodium, magnesium and iron Ans : [CBSE 2011]
react with air and water is an indication of their It is because Al itself is a strong reducing agent,
relative positions in the ‘reactivity series’. Is this therefore it cannot be reduced by carbon.
statement true? Justify your answer with example.
Ans : [CBSE 2011] 85. A metal A which is used in thermite process, when
heated with oxygen gives an oxide B which is
Yes, Na reacts vigorously with cold water because it
amphoteric in nature. Identify A and B. Write down
is highly reactive. Magnesium reacts with hard water
the reactions of oxide of B with HCl and NaOH.
because it is less reactive than sodium. Iron reacts
only with steam because it is less reactive than Mg: Ans : [CBSE 2011]
2Na(s) + MgO(s) $ Na2O(s) + Mg A is Aluminium
3Mg + Fe2O3 $ 3MgO + 2Fe. 2Al + 3O2
Heat
Al2O3(S)
Al2O3 is an amphoteric oxide:
79. What are amphoteric oxides? Give two examples.
Al2O3 + 2NaOH $ 2NaAlO2 + H2O
Ans : [CBSE 2011] Al2O3 + 6HCl $2AlCl3 + 3H2O
Those oxides which react with acids as well as bases
are called amphoteric oxides e.g., Al2O3 and ZnO. 86. A substance X which is an oxide of metal is intensively
used in cement industry. The element is present in
80. X + YSO4 $ XSO4 + Y our bones also. On treatment with water, it forms a
Y + XSO4 $ No reaction solution which turns red litmus blue. Identify X and
Out of the two elements, X and Y, which is more also write the chemical reactions involved.
reactive and why? Ans : [CBSE 2011]
Ans : [CBSE 2011] X is calcium. Its oxide, CaO is used in cement industry.
X is more reactive than Y because it is displacing Y Calcium is also present in bones.
from its salt solution. Ca(s) + 2H2O(l) $ Ca(OH)2(aq) + H2(g)
Calcium hydroxide turns red litmus blue.
81. What is an alloy? State the constituents of solder.
Which property of solder makes it suitable for welding 87. Elements magnesium and oxygen respectively belong
electrical wires? to group 2 and group 16 of the Modern Periodic
Ans : [CBSE 2011] Table. If the atomic numbers of magnesium and
oxygen are 12 and 8 respectively, draw their electronic
Alloy is a homogeneous mixture of two or more metals. configurations and show the process of formation of
One of them can be a non- metal also. their compound by transfer of electrons.
Alloys are made by melting two metals together Ans : [CBSE 2010]

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Chap 3 : Metals and Non-Metals www.cbse.online

series of metals help in predicting the relative

activity of various metals?
(b) Suggest different chemical processes used for
obtaining a metal from its oxides of metals in the
middle of the reactivity series and metals at the
top of the reactivity series. Support your answer
with one example each.
88. Write a balanced chemical equation for representing
Ans : [CBSE Sample Paper 2017-2018]
the chemical reaction between manganese dioxide
and aluminium powder. What happens if manganese (a) The series in which metals are arranged in
powder is heated with aluminium oxide? decreasing order of reactivity is called activity
Ans : [CBSE 2010] series of metals. The metal at the top is most
reactive, followed by less reactive metal and so on.
3MnO2 + 4A1 $ 2Al2O3 + 3Mn The metal at the bottom of activity series is least
No reaction will take place if manganese powder is reactive.
heated with Al2O3 because Mn is less reactive than Al. (b) Metals at the top of activity series are obtained
89. If a strip of aluminium with scratched clean surface
by electrolytic reduction e.g.,
is dipped into an aqueous solution of copper sulphate NaCl $ Na+ + Cl-
(Molten)
for a little time, the surface of the strip becomes At cathode :
brownish. What is the reason for this? Write the Na+ + e- $ Na
balanced chemical equation for this. At anode:
Ans : [CBSE 2010]
Cl- e- $ Cl
Aluminium is more reactive than copper, Cl + Cl $ Cl 2
2Al(s) + 3CuSO4(aq) $ Al2(SO4)3(aq) + 3Cu(s) Metals in the middle of the reactivity series are
90. Zinc does not evolve hydrogen gas on reacting with obtained by reduction with A1 e.g.,
HNO3. Why? Cr2O3 + 2Al $ Al2O3 + 2Cr
Ans : [CBSE 2010] 94. a. Write the steps involved in the extraction of pure
Dilute HNO3 is an oxidising agent, therefore it does metals in the middle of the activity series from
not liberate H2 with zinc. It oxidises N and liberates their carbonate ores.
NO gas (Nitrogen monoxide). b. How is copper extracted from its sulphide ore?
Explain the various steps supported by chemical
91. Write the electron dot structure for sodium and equations. Draw a labelled diagram for the
chlorine atoms. How do these atoms form a chemical electrolytic refining of copper
bond? Name the type of bond so formed. Why does a Ans : [CBSE 2016]
compound so formed have high melting point?
a. Following steps are involved in the
Ans : [CBSE Sample Paper 2008-2009]
i. Hydraulic washing: The carbonate ores is washed
, are electron dot structure of Na and chlorine with stream of water to remove earthly impurities.
atoms. Sodium can lose an electron and Cl gains that ii. Calcination: Carbonate ores is heated strongly in
electron and they form an ionic bond. the absence of air to form oxides e.g.,
Heat
ZnCO3 ZnO + CO2
iii. Reduction: ZnO is reduced with carbon to get Zn:
ZnO + C $ Zn + CO
iv. Electrolytic refining: Impure zinc is made as
anode, pure Zn is taken as cathode, acidified
It has high melting point due to strong forces of ZnSO4 of electrolyte’is used to get pure metal:
attraction between Na+ and Cl- ions. At anode: Zn $ Zn2+ + 2e-
(Impure)

92. Give reason for the following: At cathode: Zn2+ + 2e- $ Zn(s)
(Pure)
a. Metals can be given different shapes according to
b. Copper sulphite is concentrated by froth floation
our needs.
process.
b. Hydrogen is not evolved when a metal reacts with
i. 2Cu2S + 3O2 $ 2Cu2O + 2SO2
nitric acid.
ii. Reduction: Cu2S + 2Cu2O $ 6Cu + SO2
Ans : [CBSE 2008(C)] iii. Electrolytic refining:
a. Metals are malleable, therefore they can be given At cathode: Cu2+ + 2e- $ Cu
(pure)
different shapes.
At anode: Cu $ Cu2+ + 2e-
b. It is because HNO3(dil.) is a good oxidising agent. (Impure)

Acidified CuSO4 is taken as electrolyte.

THREE MARKS QUESTIONS

93. (a) What is reactivity series? How does the reactivity

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Chap 3 : Metals and Non-Metals www.cbse.online

2. Set up the apparatus as shown in the diagram.

3. Plug the switch ON so that current starts flowing.
4. Record your observations.
5. Repeat the procedure with other metals.
Observation: The bulb glows with all metals.
Conclusion: Metals are good conductors of electricity.

95. Explain the following statements:

a. Most metal oxides are insoluble in water but some
of these dissolve in water. What are these oxides
and their solution in water called?
b. At ordinary temperature the surface of metals
such as magnesium, aluminium, zinc etc. is covered 99. a. What is an alloy? How is it prepared? Give two
with a thin layer. What is the composition of this examples of alloys.
layer? State its importance. b. Iron is not used in pure state. Give reason.
c. Some alkali metals can be cut with knife. Ans :
Ans : [CBSE 2016]
a. Alloy is a homogeneous mixture of two or more
a. These oxides are basic in nature and their solution metals. One of them can be a non-metal also.
are called alkalies. Alloys are made by melting two metals together
b. The composition of this layer is metal oxide. It and then cooling it. Example: Brass and Bronze
prevents the metal from corrosion. b. Iron gets rusted, therefore it is not used in pure
c. Sodium can be cut with a knife because it is a state.
very soft metal.
100. A metal P when exposed to moist air for a longer
96. Write one example of each of the following: period of time, loses its shining brown surface and
a. Most malleable and most ductile metal. attains a green coating; what has happened? Identify
b. The best conductor of heat and poorest conductor the metal, write the name and chemical formula of
of heat. green coloured compound. List two ways to prevent
c. ‘A metal with highest melting point and a metal this process.
with lowest melting point. Ans : [CBSE 2016]
Ans : [CBSE 2016]
It undergoes corrosion. The metal is copper.
a. Gold is most malleable and ductile. Chemical formula of green coloured compound is
b. Copper is the best conductor and lead is a poor CuCO3.Cu(OH)2
conductor of heat copper. a. It can be prevented by coating of tin over iron.
c. Tungsten has highest melting point, mercury has b. It can also be prevented by coating it with paint.
lowest melting point.
101. Name the constituent elements of alloys:
97. Aluminium oxide and zinc oxide react with both acids a. Brass,
and bases to produce salt and water. What are these b. Bronze,
oxides called? Write chemical equations in each case. c. Solder.
Ans : [CBSE 2016] Mention one use of each alloy.
These are called amphoteric oxides: Ans : [CBSE 2016]
Al2O3 + 2NaOH $ 2NaAlO2 + H2O a. Brass is made up Cu and Zn. It is used for making
ZnO + 2NaOH $ Na2ZnO2 + H2O decorative articles.
ZnO + 2HCl $ ZnCl2 + H2O b. Bronze is made up of Cu and Sn. It is used for
Al2O3 + 6HCl $ 2AlCl3 + 3H2O making statues, medals.
c. Solder it is an alloy of Pb and Sn. It is used for
98. Describe an activity to show that metals are good soldering purposes.
conductors of electricity.
Ans : [CBSE 2016] 102. Give reasons only:
a. We can store copper sulphate solution in a silver
Activity: To show metals are good conductors of
vessel but not silver nitrate solution in copper
electricity.
vessel.
1. Take copper wire and insert two clips with a
b. The reaction of zinc with dilute HNO3 does not
sample to be inserted between them, as shown in
produce H2 gas.
the diagram.

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Chap 3 : Metals and Non-Metals www.cbse.online

c. Food cans are coated with tin rather than zinc. is malleable and ductile.
Ans : [CBSE 2016] c. Sulphur does not conduct electricity whereas
magnesium conducts electricity.
a. It is because copper is more reactive than silver,
it will displace Ag from AgNO3 solution. Thus 106. A metal forms an oxide having formula M2O3. It
we can’t store AgNO3 in a copper container but dissolves both in dilute sulphuric acid as well as dilute
CuSO4 can be stored in silver vessel as no reaction sodium hydroxide solution. Identify the metal and
will take place because silver is less reactive. write the equations for the reactions involved.
b. Dilute HNO3 is an oxidising agent. Ans : [CBSE 2015]
c. Tin is less reactive and less expensive than zinc.
The metal is Al. Its oxide is Al2O3.
103. Name a metal in each case: Al2O3 + 2NaOH $ NaAlO2 + H2O
a. It displaces hydrogen gas on reaction with nitric Al2O3 + 3H2SO4(aq) $ Al2(SO4)3(aq) + 3H2O(l)
acid.
b. It does react with any physical state of water. 107. State the conditions under which the following metals
c. It does not react with cold water or hot water, but react with water. Write chemical equation for its
reacts with steam. reaction with each: (a) Na (b) Mg (c) Fe
Ans : [CBSE 2015] Ans : [CBSE 2015]
a. Mg and Mn (a) Sodium metal reacts with cold water as:
b. Cu 2Na + 2H2O $ 2NaOH + H2
c. Iron (b) Magnesium reacts with hot water as:
Mg + 2H2O $ Mg(OH)2 + H2
104. Distinguish between the following: (c) Iron reacts with steam as:
a. Electrolytic reduction and electrolytic refining. 3Fe + 4H2O $ Fe3O4 + 4H2
b. Mineral and ore.
c. Alloys and amalgams 108. What is cinnabar? How is metal extracted from
cinnabar? Explain briefly.
Ans : [CBSE 2015]
Ans : [CBSE 2015]
Electrolytic reduction Electrolytic refining Cinnabar (HgS) is an ore of mercury.
Roasting: HgS(s) + O2(g) $ 2Hg(l) + SO2(g)
Metal is obtained by Metal is refined by
Cinnabar, on roasting gives Mercury and sulphur
electrolysis of molten taking impure metal as
dioxide. Mercury can be purified by the process of
ore. anode, pure metal as
distillation.
cathode and soluble salt
of metal as electrolyte 109. a Write the electron dot structure of Potassium (19)
and by passing electric and Chlorine (17).
current. b. Show the formation of KCl by transfer of electrons.
Mineral ore c. Name the ions present in the compound, KCl.
Naturally occurring Naturally occurring Ans : [CBSE 2015]
substances from substances from which a. and are electron dot structures.
which metal may or metal is extracted
may not be extracted profitably e.g., Bauxite b.
economically e.g., Mica. is an ore of Al.
Alloys amalgams
Homogeneous mixture of Homogenous mixture
two or more metals. One of mercury with any
of them can be a non- other metals e.g., zinc c. and ions are present in KCl.
metal also e.g., steel. amalagam. 110. a.Write the electron-dot structure of calcium and
sulphur.
105. State three reasons for the following facts: b. Show the formation of CaS by transfer of electrons.
a. Sulphur is a non-metal. c. Name the ions present in the compound, CaS.
b. Magnesium is a metal. Atomic number of Ca = 20, S = 16.
One of the reason must be supported with a chemical
Ans : [CBSE 2015]
equation.
Ans : [CBSE 2015] a. and
a. Sulphur is a non-metal because it reacts with O2 b.
to form SO2 which is an
acidic oxide: S + O2 $ SO2
Magnesium is a metal which reacts with O2 to
form basic oxide:
2Mg + O2 $ 2MgO c. and are present in CaS.
b. Sulphur is not malleable and ductile, magnesium

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Chap 3 : Metals and Non-Metals www.cbse.online

111. Give one most suitable word for the following Heat
statements: c. Cr2O3(s) + 2Al(s) Al2O3(s) + 2Cr(l)
a. Metal oxides which show basic as well as acidic
116. A, B and C are three elements which undergo chemical
behaviour.
reactions according to the following equations:
b. Some metals produce a sound on striking with a
A2O3 + 2B $ B2O3 + 2A ,
hard surface.
3CSO4 + 2B $ B2(SO4)3 + 3C
c. Iodine, shining non-metal.
3CO + 2A $ A2O3 + 3C
Ans : [CBSE 2015] a. Which element is most reactive?
a. Amploteric oxide, b. Which element is the least reactive?
b. Sonorous, c. What type of reactions is listed above?
c. Lustrous. Ans : [CBSE 2014]
112. State the property utilised in the following: a. B is most reactive.
a. Graphite in making electrodes. b. C is least reactive.
b. Electric wires are coated with polyvinyl chloride c. Displacement reactions.
(PVC) or rubber like materials.
117. List three properties of sodium in which it differs from
c. Metal alloys are used for making bells and strings
general physical properties of most metals.
of music instruments.
Ans : [CBSE 2014]
Ans : [CBSE 2015]
a. It is soft.
a. Graphite is a good conductor of electricity.
b. It has low melting and boiling point.
b. PVC is an insulator, protects us from electric
c. It is not malleable and ductile.
current.
c. Alloys are stronger and more sonorous than metals NO NEED TO PURCHASE ANY BOOKS
and used for bells and musical instruments. They
For session 2019-2020 free pdf will be available at
do not get rusted.
www.cbse.online for
113. Write chemical equations for the reactions taking 1. Previous 15 Years Exams Chapter-wise Question
place when: Bank
a. Iron reacts with steam. 2. Previous Ten Years Exam Paper (Paper-wise).
b. Magnesium (Mg) reacts with dilute HCl. 3. 20 Model Paper (All Solved).
c. Copper is heated in air. 4. NCERT Solutions
Ans : [CBSE 2014] All material will be solved and free pdf. It will be
Heat
provided by 30 September and will be updated regularly.
a. 3Fe(s) + 4H2O(g) Fe3O4(s) + 4H2(g) Disclaimer : www.cbse.online is not affiliated to Central Board of Secondary Education,
New Delhi in any manner. www.cbse.online is a private organization which provide free
b. Mg(s) + 2HCl(dil.) $ MgCl2(aq) + H2(g) study material pdfs to students. At www.cbse.online CBSE stands for Canny Books
For School Education
c. 2Cu(s) + O2(g) $ 2CuO(s)

114. How metals can be differentiated from non-metals on

118. Describe ionic compounds on the basis of following
the basis of any of it three chemical roperties?
properties:
Ans : [CBSE 2014] a. Strong forces of attraction between positive and
negative ions.
Metal Non-metals b. Solubility of compounds in water.
1. Metallic oxides are Non-metallic oxides are c. Electrical conductivity.
basic in nature. acidic in nature Ans : [CBSE 2014]
2. Most of metals Non-metals do not lib- a. They have high melting and boiling points.
liberate H2 gas with erate H2 gas with dilute b. They are soluble in water.
dilute acids. acids. c. They conduct electricity in molten state and in
aqueous solution.
3. Metal hydroxides, Non metallic oxides form
bases turn red acid in aqueous solution, 119. a.Name the metal which does not stick to the glass,
litmus blue. which turns blue litmus b. Name a metal which is commonly used in thermite
red. welding.
c. What is the nature of Zinc oxide?
115. Write chemical equations for the reactions taking Ans : [CBSE 2014]
place when:
a. Iron is strongly heated with air. a. Mercury.
b. Lead carbonate is calcined. b. Aluminium displaces molten iron from Fe2O3
c. Chromium oxide (Cr2O3) is heated with aluminium which is used in thermite reaction for welding
powder. purpose.
c. It is amphoteric.
Ans : [CBSE 2014]
a. 3Fe(s) + 2O2(g)
Heat
Fe3O4(s) 120. a.Define the term ‘anode mud’. Name an electrode
made of pure metal.
Heat
b. PbCO3(s) PbO(s) + CO2(g) b. Give the reactions taking place at cathode and
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Chap 3 : Metals and Non-Metals www.cbse.online

anode during the electrolytic refining of copper. The process in which iron reacts with oxygen in the
Ans : [CBSE 2014] presence of moisture to form brown layer on its surface
is called rusting.
a. The impurities left behind at anode after impure
copper metal undergoes electrolytic refining is
called anode mud.
b. At anode:
Cu (s) $ Cu2+ (aq) + 2e-
(impure)
At cathode:
Cu2+ (aq) + 2e- $ Cu (s)
(Pure)

121. Name two metals which are purified by electrolytic

refining. Mention the cathode, anode and electrolyte
used in the refining process. At which electrode would
the pure metal be deposited?
Ans : [CBSE 2014]
Cu, Zn, Al can be purified by electrolytic refining
method:
At cathode, pure metal is deposited. Cathode is made
up of pure metal. Anode is made up of impure metal.
Soluble salt of metal is used as electrolyte.
126. a.Show the formation of Na2O by transfer of
122. Write the balanced chemical equation in each case: electrons between the combining atoms.
a. Mg metal is reacted with very, little amount of b. Why are ionic compounds usually hard?
dilute HNO3. c. How is it that ionic compound in the solid state
b. Aluminium powder is added to Fe2Og. do not conduct electricity but they do so in the
c. Zinc sulphide is roasted. molten state?
Ans : [CBSE 2014] Ans : [CBSE 2012]
a. Mg (s) + 2HNO 3 (S) $ Mg (NO 3) 2 (aq) + H 2
a.
3Mg (s) + dil.HNO 3 $ Mg (NO 3) 2 + 2NO + 4H 2 O
b. 2A1 + Fe2O3 $ Al2O3 + 2Fe
c. 2ZnS + 3O2 $ 2ZnO + 2SO2

123. Suggest a method of reduction for the following metals

during metallurgical processes:
a. Metal A which is one of the last, second or at the b. Ionic compounds are hard due to strong forces of
third position in the reactivity series. attraction between oppositely charged ions.
b. Metal B which gives vigorous reaction even with c. In solid state, ions are not free to move but in
water and air. molten state, ions are free to move.
c. Metal C which is kept in the middle of the activity
series. 127. Define the terms: (a) mineral, (b) ore and (c) gangue
Ans : [CBSE 2013] Ans : [CBSE 2012]
a. Reduction with carbon. a. Mineral: It is a naturally occurring substance
b. Electrolytic reduction. from which metal may or may not be extracted
c. Reduction with Al. economically e.g., Mica.
b. Ores: These are naturally occurring substances
124. a.Explain the formation of ionic compound CaO from which metal can be extracted profitably e.g.,
with its electron dot structure. Atomic number of Haematite.
Ca = 20, O = 8. c. Gangue: The impurities present in the ore is called
b. Name the constituents of bronze. gangue e.g., SiO2.
Ans : [CBSE 2012]
128. An ore on heating in air produces sulphur dioxide.
a. Which process would you suggest for its concentration?
Describe briefly any two steps involved in the
conversion of the concentrated ore into the related
metal.
Ans : [CBSE 2009]
b. Bronze is made up of Copper and Tin. It is concentrated by using froth floatation process.
a. Roasting: The ore is heated in the presence of
125. What is meant by rusting? With labelled diagrams,
oxygen to form oxide e.g.,
describe an activity to find out the conditions in
2ZnS + 3O2 $ 2ZnO + SO2
which rusting takes place.
b. Reduction: ZnS is reduced by ZnO to get Zn and
Ans : [CBSE 2012] SO2. Carbon can also be used to reduce ZnO to
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Chap 3 : Metals and Non-Metals www.cbse.online

Zn:
ZnS + 2ZnO $ 3Zn + SO2
ZnO + C $ Zn + CO

129. Observe the two test tubes A and B as shown in b. It is an ionic compound.
the diagram given below and answer the following 1. It is soluble in water.
questions : 2. It conducts electricity in molten state and in
aqueous solution.
3. It is a hard solid.

132. a.What type of ores are calcined? Illustrate with

suitable examples.
b. In what form calcined ore is obtained and how it
can be reduced? Give chemical equation for the
reduction process involved for the example given
by you.
c. Name any two metals used as reducing agents
by displacing metals of low reactivity from their
compounds.
a. In which test tube will the reaction take place?
b. Write a balanced chemical equation for the Ans : [CBSE 2015]
reaction. a. Carbonate ores are calcined e.g.,
Heat
c. Name the type of reaction. CuCO3(s) CuO(s) + CO2(g)
Ans : [CBSE 2008(C)] b. It is obtained in oxide form. It is reduced by using
a suitable reducing agent e.g.,
a. In the first test tube reaction will take place. Heat
b. Fe(s) + CuSO4(aq) $ FeSO4(aq) + Cu(s) CuO(s) + C Cu(s) + CO(g)
c. Displacement reaction. c. Al and Mg.

133. a.An ore on treatment with dilute hydrochloric acid

FIVE MARKS QUESTIONS produces brisk effervescence. What kind of ore is
this? What steps will be required to obtain metal
from the enriched ore?
130. a.Define corrosion. b. Copper coin is kept immersed in silver nitrate
b. What is corrosion of iron called? solution for sometime. What change .will take
c. How will you recognise the phenomena of corrosion place in the coin and in the colour of the solution?
of silver? Write a balanced chemical equation for the
d. Why corrosion of iron metal is a serious problem? reaction.
e. How can we prevent corrosion of iron? Ans : [CBSE 2014]
Ans : [CBSE 2016] a. It is a carbonate ore.
a. Corrosion: The process in which a metal react (i) Hydraulic washing, (ii) Calcination,
with substances present in atmosphere to form (iii) Reduction, (iv) Refining.
surface compounds is called corrosion. b. The solution will become blue in colour, blackish
b. Corrosion of iron is called rusting. silver metal will get deposited:
c. It turns black on corrosion due to the formation Cu ^ s h + 2AgNO 3 ^aqh $ Cu ^NO 3h2 ^aqh + 2Ag ^ s h
of Ag2S.
d. It weakens bridges and materials and a lot of iron 134. a.Define activity series of metals. Arrange the
gets wasted every year. metals: gold, copper, iron and magnesium in the
e. We can prevent corrosion of iron by order of their increasing reactivity.
1. Painting, b. What will you observe when:
2. Oiling and greasing, (1) Some zinc pieces are placed in copper sulphate
3. Galvanisation, solution.
4. By forming its alloys. (2) Some silver pieces are placed into green
coloured ferrous sulphate solution.
131. a.Write electron dot diagrams of chlorine (At. No. Ans : [CBSE 2013]
17) and calcium (At. No. 20). Show the formation
of calcium chloride by transfer of electrons. a. The series in which metals are arranged in
b. Identify the nature of the above compound decreasing order of reactivity is called activity
and explain three physical properties of such a series of metals. The metal at the top is most
compound. reactive, followed by less reactive metal and so on.
The metal at the bottom is least reactive.
Ans : [CBSE 2015] Au < Cu < Fe < Mg is the increasing order of
a. reactivity.
b. (1) The solution will become colourless, reddish
brown copper metal will get deposited:
Zn(s) + CuSO4(aq) $ ZnSO4(aq) + Cu(s)

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Chap 3 : Metals and Non-Metals www.cbse.online

(2) No reaction will take place because Ag is less 2Al(s) + Fe2O3(s)

Heat
Al2O3(l) + Fe(l)
reactive than Fe. A B D (Iron)
C

135. A metal (E) is stored under kerosene oil. When a small This reaction need heat to start but it is highly
piece of it is left open in air, it catches fire. When exothermic.
the product formed is dissolved in water, it turns red This reaction belongs to the category of:
litmus blue. (1) Displacement reaction,
a. Name the metal (E). (2) Redox reaction.
b. Write the chemical equation for the reaction 137. Four metals A, B, C and D are added to the following
when it is exposed to air and when the product is aqueous solutions one by one. The observations made
dissolved in water. are tabulated below:
c. Explain the process by which metal is obtained
from its molten chloride. Iron (II) Copper (II) Zinc Silver nitrate
Ans : [CBSE 2012,2011] sulphate sulphate sulphate
A No Reaction Reddish Brown .......... ..........
a. E is sodium metal. Deposit
b. 2Na + 2H2O $ 2NaOH + H2
B Grey Deposit .......... No Reaction ..........
H2 gas will catch fire.
NaOH turns red litmus blue. C No Reaction No Reaction No Reaction White Shining
4Na(s) + O2(s) $ 2Na2O(s) Deposit
Na2O + H2O(aq) $ 2NaOH(aq) D No Reaction No Reaction No Reaction No Reaction
c. It is obtained by electrolytic reduction e.g., ‘Na’
metal is obtained by electrolysis of molten NaCl: Answer the following questions based on the above
NaCl
Electrolysis
N+ + Cl- observations:
Molten a. Which is the most active metal and why?
At cathode: Na+ + e- $ Na b. What would be observed if B is added to copper
At anode: Cl- $ Cl + e- (II) sulphate solution and why?
Cl + Cl $ Cl2 c. Arrange the metals A, B, C and D in order of
increasing reactivity.
136. a.Write two differences between calcination and d. Container of which metal can be used to store
roasting. [CBSE 2012] both zinc sulphate solution as well as silver nitrate
b. ‘No reaction takes place when granules of a solid solution?
‘A’ is mixed with a powder of solid ‘B’. However e. Which of the above solutions can be easily stored
when the mixture is heated, a reaction starts with in a container made up of any of these metals?
the evolution of much heat. Product ‘C’ of the
Ans : [CBSE Sample Paper 2009]
reaction settles down as a liquid metal and a solid
product ‘D’ keeps on floating over the liquid ‘C’. a. B is the most reactive because it displaces Fe. It
This reaction is sometimes used for making metals will displaces Fe. It will displace Cu as well as Ag
for ready use in odd places. also.
a. Based on this information, make assumptions b. B will displace copper from CuSO4 solution
about metals ‘A’ and ‘B’ and corresponding because it is more reactive than Cu.
deductions about ‘C’ and ‘D’ and write a balanced c. D is least reactive and D<C<A<B is the
chemical equation for the reaction. Include in increasing order of reactivity.
the chemical equation about the physical states d. Container of metal D can be used to store both
of the reactants and products, need for heating ZnSO4 and AgNO3.
for starting the reaction and the reaction being e. Zinc sulphate solution can be stored in container
exothermic. made up any of the metals A, B, C, D because none
b. Name two types of chemical reactions to which of them could displace zinc from zinc sulphate as
this reaction can belong to. these are less reactive than zinc.
Ans : [CBSE 2012] WWW.CBSE.ONLINE

a. Differences between calcination and roasting. NO NEED TO PURCHASE ANY BOOKS

Roasting Calcination For session 2019-2020 free pdf will be available at

www.cbse.online for
1. It is done in the It is done in the
1. Previous 15 Years Exams Chapter-wise Question
presence of oxygen. absence of oxygen.
Bank
2. It is done with It is done with 2. Previous Ten Years Exam Paper (Paper-wise).
sulphide ores eg. carbonate ores e.g. 3. 20 Model Paper (All Solved).
Heat
2ZnS + 3O2 FeCO3 4. NCERT Solutions
$ FeO(s) + All material will be solved and free pdf. It will be
2ZnO + CO2(g) provided by 30 September and will be updated regularly.
Disclaimer : www.cbse.online is not affiliated to Central Board of Secondary Education,
2SO2 New Delhi in any manner. www.cbse.online is a private organization which provide free
study material pdfs to students. At www.cbse.online CBSE stands for Canny Books
b. A is Al, B is Fe2O3, C is molten Iron, D is Al2O3 For School Education
(Molten)

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