Roll No.
: Time -
Date : MM - 27
Which of the following metals exist in their native state in nature ? 1
(i) Cu (ii) Au (iii) Zn (iv) Ag
(a) (i) and (ii) (b) (ii) and (iii)
(c) (ii) and (iv) (d) (iii) and (iv)
Ans : (c)
2. Observe the two test tubes A and B in the diagram given below and answer the following 3
questions:
(a) In which test tube will the reaction take place ?
(b) Write a balanced equation for the reaction.
(c) Name the type of reaction.
Ans : (a) In first test tube reaction will take place.
(b) Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)
(c) Displacement reaction
3. (a) What are amphoteric oxides? Choose the amphoteric oxides from amongst the following 3
oxides:
Na2O, ZnO, Al2O3, CO2, H2O
(b) Why is that non-metals do not displace hydrogen from dilute acids?
Ans : (a) Those oxides which are both acidic as well as basic are called amphoteric oxides,
e.g. Al2O3, ZnO.
(b) It is because non-metals do not supply electrons to change H+ ions into hydrogen
gas.
4. (a) Write the electron dot structures for potassium and chlorine. 3
(b) Show the formation of KCl by the transfer of electrons.
(c) Name the ions present in this compound, KCl.
Ans :
5. (a) Show the formation of Na2O by the transfer of electrons between the combining atoms. 3
(b) Why are ionic compounds usually hard?
(c) How is it that ionic compounds in the solid state do not conduct electricity but they do so when
in molten state?
Ans :
(b) It is due to strong force of attraction between oppositely charged ions.
(c) In solid state, ions are not free to move whereas in molten state ions are free to move,
therefore, they conduct electricity in molten state.
(a) Write the steps involved in the extraction of pure metals in the middle of the activity series 5
from their carbonate ores.
(b) How is copper extracted from its sulphide ore? Explain the various steps supported by chemical
equations. Draw labelled diagram for the electrolytic refining of copper.
Ans : (a) (i) Concentration of ore
(ii) Calcination
(iii) Reduction
(iv) Purification
(b) (i) Ore of copper is concentrated by froth floatation process.
(ii) Roasting:
2CuFeS2 + O2 → Cu2S + FeS + SO2
2Cu2S + 3O2 → 2Cu2O + 2SO2
2FeS + 3O2 → 2FeO + 2SO2
FeO + SiO2 → FeSiO3
(iii) Smelting:
2Cu2O + Cu2S → 6Cu + SO2
(iv) Electrolytic refining: Impure copper is taken as anode, pure copper is taken as
cathode. Acidified CuSO4 is taken as electrolyte. Impure copper changes into Cu2+
which gain electron at cathode forming pure Cu. Impurities are left behind as anode
mud.
At anode Cu (impure) → Cu2+ + 2e–
At cathode Cu2+ + 2e– → Cu (pure)
Shivam helps his friend Rohan in studies. Shivam is topper in the class. Rohan also improved his 4
performance. They like each other and they are good friends.
(a) What values are possessed by Shivam?
(b) What type of bond exists between Rohan and Shivam?
(c) Why are ionic bonds strong?
Ans : (a) Shivam has helping nature.
(b) It is like ionic bond.
(c) Ionic bond are strong due to strong force of attraction between oppositely charged
ions.
8. Mg reacts with 5% of HNO3 and gives 1
(a) MgNO3 + 2H2
(b) Mg(NO3)2 + H2O
(c) Mg(NO3)2 + H2
(d) MgNO3 + H2O
Ans : (c) Mg + 2HNO3(5%) → Mg(NO3)2 + H2
9. The compound obtained on reaction of iron with steam is/are: [CBSE 2020] 1
(a) Fe2O3
(b) Fe3O4
(c) FeO
(d) Fe2O3 and Fe3O4
Ans : (b) 3Fe(s) + 4H2O(g) → Fe3O4 + 4H2(g)
10. Which of the following is not an ionic compound? 1
(a) KCl
(b) MgCl2
(c) CCl4
(d) NaCl
Ans : (c) It is covalent compound.
11. When zinc reacts with sodium hydroxide, the product formed is [CBSE 2023] 1
(a) Sodium oxide
(b) Sodium zincate
(c) Zinc hydroxide
(d) Zinc oxide
Ans : (b) Zn + 2NaOH → Na2ZnO2 + H2
12. Direction: In the following Questions, the Assertion and Reason have been put forward. Read the 1
statements carefully and choose the correct alternative from the following:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the
Assertion.
(b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the
Assertion.
(c) Assertion is true but the Reason is false.
(d) The statement of the Assertion is false but the Reason is true.
Assertion: Sodium oxide is an amphoteric oxide.
Reason: Those oxides which react with acid as well as base are amphoteric oxides. [CBSE 2023]
Ans : (d) Assertion is false but Reason is true.
