MCQ Electrolysis

1.What is electrolysis?
a)breaking down of a compound using a current
b)making a compound using a current
c)a and b
d)none of the above

2.What kind of Electrical Current does Electrolysis require?

a)Direct
b)Indirect
c)Anternative
d)A alternating

3.Which statement correctly describes the 2 electrodes?

a)The anode is negative and the cathode is positive
b)The anode and cathode are both positive
c)The anode is positive and the cathode is negative
d)The anode and cathode are both negative.

4.What is the name given to the solution that is being electrolysed?

a)Salt solution
b)Electric solution
c)Mineral solution
d)Electrolyte

5.Explain why the electrolyte has to be a liquid.

a)So the ions can move
b)So the electrons can move
c)So that it doesn't get too hot
d)So the current does not pass

6.It is essential that the electrolyte is a liquid so that...

a)Charged ions can not migrate towards the electrodes.
b)Charged ions can migrate towards the electrodes.
c)The solution can move around.
d)The current can flow through it.

7.What happens at the positive electrode?

a)Positive non-metal ions are attracted
b)Positive metal ions are attracted
c)Negative non-metal ions are attracted
d)Negative metal ions are attracted

8.Positive ions (cations) will move towards the cathode (-) where they will discharge
by....
a)Breaking apart
b)Losing electrons
c)Clumping together.
d)Gaining electrons

9.When copper sulphate solution is electrolysed using a carbon electrode what forms at
the anode?
a)Hydrogen
b)Oxygen
c)Copper
d)Sulphur dioxide

10.What does Cathode (-) do to ions?

a)Give electrons to the Positive ions to turn them back into atoms
b)Take electrons from the positive ions?
c)Turn ions back into atoms by removing electrons
d)Turn atoms into ions by adding electrons

11.What is the equation to show what happens to Cl ions at the anode.

a)Cl- --> Cl + e-
b)2Cl- --> Cl2 + 2e-
c)Cl2 + 2e- 2Cl-
d)Cl2 + 2e- --> 2Cl-

12.Choose the half-equation that shows the discharge of aluminium ion.

a)Al3+ - 3e- --> Al
b)Al2+ + 3e- --> Al
c)Al3+ + 3e- --> Al
d)Al3+ --> Al + 3e-

13.Ionic compounds do not conduct electricity when they are solid because,
a)their electrons are not free to move
b)their ions are free to move
c)their ions are not free to move
d)their electrons are free to move

14.In an aqueous solution of copper chloride, which ions are attracted to the negative
electrode?
a)Cu2+ and Cl- and H+ and OH-
b)Cu2+ and H+
c) Cl- and OH-
d)Cu2+

15.What change is observed at cathode during electrolysis of aqueous copper(II)

chloride using carbon electrode
a)Nothing
b)pink solid deposit
c)bubbles of green gas
d)colourless gas

16.What are the ions present in molten Al2O3?

a)Al2+ and O3-
b)Al2- and O3+
c)Al3+ and O2-
d)Al3- and O2+

17.Oxidation is the loss of electrons. Where does oxidation take place during
electrolysis.
a)At anode
b)In the electrolyte
c)At the circuit
d)At cathode

18.

The diagram shows the electrolysis of lead(II) bromide using inert electrodes. Why does
the bulb only light up when the lead(II) bromide is melted?
a)Bromine atoms in lead(II) bromide are converted to ions when it is melted
b)Electrons flow through the lead(II) bromide when it is melted
c)The ions in lead(II) bromide are mobile charge carriers in the molten state.
d)There are no ions in solid lead(II) bromide
19.
What particle carries the charge in the wire?
a)electron
b)proton
c)ion
d)atom

20.
What particle carries the charge in the electrolyte?
a)electron
b)proton
c)ion
d)atom

21.When NaCl solution is electrolysed what forms at the anode?

a)Hydrogen
b)Oxygen
c)Chlorine
d)Sodium

22.What is the half-equation for the discharge of hydroxide ions?

a)2O2- --> O2 + 4e-
b)OH- --> OH + e
c)4OH- --> 2H2O + O2 + 4e-
d)2H2O + O2 + 4e- --> 4OH-

23.
The picture shows electrolysis of copper(II) sulphate solution using graphite electrodes.
Besides formation of brown solid on the cathode, what other observations can be
made?
a)The mass of graphite anode decreases
.b)The blue colour solution becomes darker.
c)Bubbles of gas form at the anode.
d)The blue colour solution becomes darker.
24.
What are the products at the electrodes when dilute sulfuric acid is electrolysed using
inert electrodes?
a)A
b)B
c)C
d)D

25.
Electricity is passed separately through concentrated hydrochloric acid, concentrated
aqueous sodium chloride and dilute sulfuric acid.In which rows are the electrolysis
products correctly named?
a)1, 2 and 3
b)1 and 2 only
c)1 and 3 only
d)2 and 3 only
26.
Which row describes the electrolysis of molten potassium bromide?
a)A
b)B
c)C
d)D

27.
What are the electrode products when molten silver iodide is electrolysed between inert
electrodes?
a)A
b)B
c)C
d)D

28.
Copper and hydrogen can each be formed by electrolysis.At which electrodes are these
elements formed?
a)A
b)B
c)C
d)D

29.What is the name of a negatively charged ion?

a)negatron
b)electron
c)cation
d)anion

30.What is the name of a positively charged ion?

a)positron
b)proton
c)cation
d)anion

31.What is the name of a negatively charged electrode?

a)cathode
b)anode
c)cation
d)anion

32.What is the name of a positively charged electrode?

a)cathode
b)anode
c)cation
d)anion
33.
What occurs during electrolysis of a molten salt?
a)Electricity is produced by a spontaneous redox reaction
b)Electricity cause a nonspontaneous redox reaction to occur
c)Electrons flow through the molten salt
d)Electrons are removed from both ions of the molten salt

34.
Object is electroplated with copper using copper(II) sulfate. Which statement is correct?
a)Positive electrode increases in mass
b)Concentration of Cu2+ ions in solution decreases
c)Reduction occurs at positive electrode
d)Reaction at negative electrode is Cu2+ + 2e– → Cu

35.Choose one inert electrodes:

a)sodium
b)silver
c)copper
d)platinum
36.The electrolytic deposition of a superior metal on a baser metal is:
a)electro-refining
b)electro-plating
c)electro-metallurgy
d)electrolysis

37.Which is the correct electrochemical series?

a)Na, Al, Fe, Mg, Zn
b)Mg, Fe, Zn, Na, Al
c)Na, Mg, Al, Zn, Fe
d)Fe, Zn, Na, Mg, Al

38.Choose incorrect reasons for electroplating:

a)Does not improve the electrical conductivity of the article.
b)Prevents corrosion or rusting of the base metal.
c)Makes the article dull.
d)Makes the article attractive.

39.During electroplating an article with silver, the electrolyte used is:

a)silver nitrate solution
b)silver cyanide solution
c)sodium argentocyanide solution
d)nickel sulphate solution

40.The blue colour of aq. Copper[II] sulphate solution ________ during electrolysis of
aq. CuSO4 using copper electrodes, but ______ when platinum electrodes are used.
a)remains unchanged ; fades
b)remains unchanged; remains unchanged
c)fades ; fades
d)None of the above

41.The particles in weak electrolytes are:

a)molecules only
b)ions and unionised molecules
c)ions only
d)All of the above

42.The preferential discharge of the ions depends on its position in the ____________
series.
a) electrochemical series
b) non reactive series
c) proton series
d) neutron series

43.When silver is being electroplated onto the cup,

a)the cup is at the anode.
b)silver is at the anode.
c)the electrolyte is aqueous gold nitrate
d)the electrolyte is aqueous silver

44.
Which factors affect the amount of metal formed during electrolysis?
a)I and II
b)I and III
c)II and III
d)I, II and III
45.
Which are used for electroplating of a metal spoon with copper?
a)I and II
b)I and III
c)II and III
d)I, II and III

46. Which statement is correct on electrolysis of aqueous

copper(II) sulfate using graphite electrodes?
a)Colourless gas is produced at negative electrode
b)Electrolyte does not change colour
c)Negative electrode decreases in mass
d)Colourless gas is produced at positive electrode

47.When NaCl solution is electrolysed what forms at the cathode?

a)Hydrogen
b)Oxygen
c)Chlorine
d)Sodium
48.
The diagram shows an electrolysis experiment.During the electrolysis, sodium was
formed at electrode P and chlorine at electrode Q.Which choice correctly identifies P, Q
and X?
a)P = anode; Q = cathode; X = concentrated solution of sodium chloride in water
b)P = anode; Q = cathode; X = molten sodium chloride
c)P = cathode; Q = anode; X = concentrated solution of sodium chloride in water
d)P = cathode; Q = anode; X = molten sodium chloride

49.
The diagram shows the electrolysis of aqueous sodium chloride.
Which choice correctly identifies P, Q and X?
a)P = Hydrogen Q = Oxygen; X = sodium chloride solution
b)P = Sodium Q = Chlorine; X = water
c)P = Sodium; Q = Oxygen X = hydrochloric acid solution
d)P = Hydrogen Q = Chlorine X = sodium hydroxide solution
50.

a)A
b)B
c)C
d)D

51.What is the removal of oxygen from a substance called?

a)reduction
b)extraction
c)electrolysis
d)oxidation
52.Identify the weak electrolyte
a)NaCl soln
b)dil HCl soln
c)dil H2SO4
d)aq acetic acid

53.Which of the following will act as non electrolyte?

a)Liq CCl4
b)CH3COOH
c)Aq. NaOH
d)Aq. KCl soln

54.
Diagram shows an electrolytic cell.Which of the substances cause the bulb to light up
brightly when electricity passes through it?
a)Ethanol
b) dil.sulphuric acid
c) formic acid
d)glucose

55.Molten X is electrolysed using carbon electrodes. After 10 minutes, a brown solid is

deposited on the cathode and a brown gas is released at the anode. What is molten X?
a)Lead(II) chloride
b)Lead(II) bromide
c)Copper(II) chloride
d)Copper(II) bromide
56.Choose the half-equation that shows the discharge of lead ions.
a)Pb2+ - 2e- --> Pb
b)Pb3+ + 3e- --> Pb
c)Pb2+ + 2e- --> Pb
d)Pb2+ --> Pb + 2e-

57.Choose the half-equation that shows the discharge of hydrogen ions.

a)H2+ - 2e- --> H
b)H1+ + 1e- --> H
c)H2+ + 2e- --> H
d)H2+ --> H + 2e-

58.Choose the half-equation that shows the discharge of Copper ions at cathode.
a) cu2+ - 2e- --> cu
b) cu2- + 2e- --> cu
c) cu2+ + 2e- --> cu
d) cu2- - 2e- --> cu

59.Choose the half-equation that shows the discharge of Copper ion at anode.
a) Cu - 1e- --> cu
b) Cu - 1e- --> cu
c) Cu - 2e- --> cu2+
d) cu2+ + 2e- --> cu

60.Choose the half-equation that shows the discharge of silver ions at anode.
a) Ag 1+ + 1e- --> Ag
b) Ag - 1e- --> Ag1+
c) Ag 2+ + 2e- --> Ag
d) Ag - 2e- --> Ag2+
61.Choose the half-equation that shows the discharge of silver ions at cathode.
a) Ag 1+ + 1e- --> Ag
b) Ag - 1e- --> Ag1+
c) Ag 2+ + 2e- --> Ag
d) Ag - 2e- --> Ag2+

62.Choose the half-equation that shows the discharge of nickel ions at cathode.
a) Ni 1+ + 1e- --> Ni
b) Ni - 1e- --> Ni 1+
c) Ni 2+ + 2e- -->Ni
d) Ni - 2e- -->Ni 2+

63.Choose the half-equation that shows the discharge of nickel ions at cathode.
a. Ni 1+ + 1e- --> Ni
b. Ni - 1e- --> Ni 1+
c. Ni 2+ + 2e- -->Ni
d. Ni - 2e- -->Ni 2+

64.Choose the half-equation that shows the discharge of bromine ion at anode.
-2
a. Br - 2e- → Br
-1
b. Br - 1e- → Br
-1
c. Br - 1e- → Br
-2
d. Br - 2e- → Br

65.Acidified solution X is electrolysed using platinum electrodes. After a few minutes, a

colorless gas which burns with pop sound is liberated on the cathode and a colorless
gas which relights the burning kindle is released at the anode. What is acidified solution
X?
a)Lead(II) chloride
b)Lead(II) bromide
c) Hydrogen oxide
d) Sodium chloride
66.
Diagram shows an electrolytic cell.Which of the substances cause the bulb not to light
up when electricity passes through it?
a)Ethanol
b)Dilute ethanoic acid
c)Solid lead(II) bromide
d)Sodium hydroxide

67..
Diagram shows an electrolytic cell.Which of the substances cause the bulb to light up
dim when electricity passes through it?
a)Ethanol
b)Dilute ethanoic acid
c)Solid lead(II) bromide
d)Tetrachloromethane

68.Which of the following will act as a strong electrolyte?

a)Liq CCl4
b)CH3COOH
c)Aq. NaOH
d)Aq. KHCO3 soln

69. Identify a group of strong electrolyte

a) sodium carbonate and sodium bicarbonate
b) sucrose and glucose
c) ethanol and ethanoic acid
d) sodium chloride and sodium hydroxide

70. Identify the group of weak electrolytes.

a. sodium carbonate and sodium bicarbonate
b. sucrose and glucose
c. ethanol and ethanoic acid
d. sodium chloride and sodium hydroxide

71. identify the group of non electrolytes.

a. sodium carbonate and sodium bicarbonate
b. sucrose and glucose
c. ethanol and ethanoic acid
d. sodium chloride and sodium hydroxide

72. Identify the cation group

a. Calcium, bromide, nitrate, sodium
b. Calcium, sodium, magnesium, potassium
c. Bromide, nitrate, sulphide, oxide
d. Chlorine, bromine, iodine,fluorine

73.identify the anion group

a. Calcium, bromide, nitrate, sodium
b. Calcium, sodium, magnesium, potassium
c. Bromide, nitrate, sulphide, oxide
d. Chlorine, bromine, iodine,fluorine
74.The particles in non electrolytes are:
a)molecules only
b)ions and unionised molecules
c)ions only
d)All of the above

75.The particles in strong electrolytes are:

a)molecules only
b)ions and unionised molecules
c)ions only
d)All of the above

76.What are the ions present in water?

a. H and OH
+ -
b. H and OH

c. H2
d. H2O

77.Which anion will get easily discharged?

a. Bromide ion
b. Iodide ion
c. Hydroxyl ion
d. Nitrate ion
78.What are the ions present in molten Lead bromide?
a. Pb and Br
2+ -
b. Pb and Br
2+
c. Pb and Br2
d. Br and H
79.What are the ions present in aqueous copper sulphate?
a. H , OH , Cu , SO4
 - 2+ 2-
b. H2, OH , Cu , SO 4

+ - 2+ 2-
c. H , OH , Cu , SO 4
2+ 2-
d. Cu , SO 4

80.What are the ions present in acidified water?

+ - 2-
a. H , OH , SO 4
+
b. H
- 2-
c. OH , SO 4

+ -
d. H , OH

81.What are the ions present in aqueous nickel sulphate?

+ -
a. H , OH
+ 2+
b. H ,Ni
+ - 2+ 2-
c. H , OH , Ni ,SO 4
- 2-
d. OH , SO 4

82. What are the ions present in aqueous sodium silver cyanide?

+ + -
a. Na , Ag , CN

+ + - -
b. Na , Ag ,OH ,CN

+ + - - +
c. Na , Ag ,OH ,CN , H

+ + - -
d. Na , Ag ,OH ,CN , H

83. What change is observed at anode during electrolysis of aqueous copper(II)

sulphate using a carbon electrode?
a) No change
b) pink solid deposit
 c) bubbles of green gas
d) colourless gas
84.What change is observed at cathode during electroplating of silver?
a. Reddish deposition
b. Silvery grey deposition
c. Blue deposition
d. No deposition
85.What change is observed at anode during electrolysis of molten lead bromide?
a. Loss in mass
b. Gain in mass
c. Colourless gas
d. Reddish brown gas
86.In electrolysis of aqueous solution of copper sulphate using copper electrode, which
ions behave as spectator ions?
2+
1.Cu ,
+
2. H ,
2-
3. SO 4

-
4. OH

a. 1 and 4
b. 2 and 3
c. 1, 3 and 4
d. 2, 3 and 4

87.Four substances are electrolysed using inert electrodes.

Which row describes the electrode products?

substance anode product cathode product

A concentrated hydrogen chlorine

aqueous sodium
chloride
 B concentrated chlorine oxygen
hydrochloric acid

C dilute sulfuric acid oxygen hydrogen

D molten lead lead bromine

bromide

88.Which statement about the electrolysis of copper(II) sulfate solution using carbon
electrodes is correct?
a. colourless gas is produced at the anode.
b. colourless gas is produced at the cathode.
c. The colour of the electrolyte remains the same.
d. The mass of both electrodes remains constant.

89. Aluminium metal is extracted from aluminium oxide by electrolysis. Which ionic
half-equation describes a reaction that occurs at the named electrode?

ionic half-equation electrode

a. 2O2– → O2 + 2e– anode

b. Al 3+ + 3e– → Al anode

c. 2O2– → O2 + 4e– cathode

d. Al 3+ + 3e– → Al cathode

90. Which changes represent oxidation?

e–
1. 2I – → I2 + 2
-
2. Cr(VI) + 1e → Cr(III)
-
3. Fe(II) - 1e → Fe(III)
a. 1 and 2
b. 1 and 3
c. 1 only
d. 2 only

91.The diagram shows apparatus used in an attempt to electroplate a metal ring with
copper.

The experiment did not work.

Which change is needed in the experiment to make it work?
a. Add solid copper(II) sulfate to the electrolyte.
b. Increase the temperature of the electrolyte.
c. Replace the copper electrode with a carbon electrode.
d. Reverse the connections to the battery.

92.Three electrolysis cells are set up. Each cell has inert electrodes.
The electrolytes are listed below.
cell 1 aqueous sodium chloride
cell 2 dilute sulfuric acid
cell 3 molten lead(II) bromide
In which of these cells is a gas formed at both electrodes?
 a. 1 and 2
b. 1 and 3
c. 2 only
d. 3 only

93.When molten lead(II) bromide is electrolysed using platinum electrodes, what is

observed at each electrode?

negative electrode positive electrode

a. bubbles of a colourless gas bubbles of a brown gas

b. bubbles of a colourless gas bubbles of a colourless gas

c. shiny grey liquid bubbles of a brown gas

d. shiny grey liquid bubbles of a colourless gas

94.Aqueous nickel(II) sulfate is used as the electrolyte to electroplate a piece of steel

with nickel. Which materials are used as the negative electrode and positive electrode?

negative electrode positive electrode

a. carbon steel

b. nickel steel

c. platinum nickel

d. steel nickel

95.The diagram shows a circuit used to electrolyse aqueous copper(II) sulfate.

Which arrows indicate the movement of the copper ions in the electrolyte and of the
electrons in the external circuit?

Copper ion Electron

a. 1 3

b. 1 4

c. 2 3

d. 2 4

96. An electrolysis experiment is carried out on different solutions, J, K and L. Electricity

is passed through each solution as shown in Figure

Any products formed at the electrodes are identified.

The results are given in Figure

Solution solution conducts Product at cathode Product at anode

electricity

J Yes Copper Chlorine

K No None None

L Yes Hydrogen Chlorine

Which of J, K and L are electrolytes?

a. K only
b. J and L only
c. K and L only
d. J, K and L

97.Which statement correctly describes the 2 - anion and cation?

a)The anion and cation are both positive
b)The anion and cation are both negative
c)The anion is positive and cation is negative
d)The cation is positive and anion is negative

98.What happens at the negative electrode?

a)Positive non-metal ions are attracted
b)Positive metal ions are attracted
c)Negative non-metal ions are attracted
d)Negative metal ions are attracted

99.Negative ions (anions) will move towards the anode (+) where they will discharge by
a)Breaking apart
b)Losing electrons
c)Clumping together.
d)Gaining electrons
100. What does anode (-) do to ions?
a)Give electrons to the Positive ions to turn them back into atoms
b)Take electrons from the positive ions?
c)Turn ions back into atoms by removing electrons
d)Turn atoms into ions by adding electrons

101. Which pair of electrolytes is not inert?

A.mercury and carbon
B. mercury and sodium
C.silver and carbon
D. copper and silver

102.when aqueous solution of sodium chloride is electrolysed

a. Chlorine is evolved at cathode
b. Hydrogen is evolved at cathode
c. Sodium is deposited at cathode
d. Sodium appears at anode
103. To prevent iron from corrosion, it is electroplated with
a. Aluminum
b. Copper
c. Zinc
d. Silver
104. Decomposition of liquid compound on passage of electricity is known as
a. Electrochemistry
b. Electrorefining
c. Electroplating
d. Electrolysis
105. In an electroplating experiment a steel cathode and a solution of nickel sulphate
electrolyte is used.What type of anode was most likely used?
a. Carbon
b. Copper
c. Iron
 d. Nickel
106. Which one of the following statements is not correct?
a. Pure water does not allow current to flow through it
b. Electrolyte only conduct when in molten state
c. Electrodes that react with electrolyte are called to be active
d. Ion must be present in electrolyte in order that it conducts electricity.
107. Which are two anions in solution of copper sulphate?
a. Sulphate and hydroxide ion
b. Copper ion and sulphate ion
c. Hydrogen ion and sulphate ion
d. Copper ion and hydrogen ion
108. If a solution of copper sulphate is electrolysed using copper electrode, then
a. Anode is reduced, cathode is oxidised
b. Anode is reduced , cathode is reduced
c. Anode is oxidised , cathode is oxidised
d. Anode is oxidised, cathode is reduced
109. The electrochemical series is formed in order of the metal regarding.
a. Position in activity series
b. Position in periodic table
c. Reactivity with other metals
d. Standard electrode potential
110. The vessel in electrolysis of molten lead bromide is carried out.
a. Clay crucible
b. Glass crucible
c. Silica crucible
d. Iron crucible
111. During silver plating of and article, the anode should be made of
a. Nickel
b. Gold
c. Silver
d. Platinum
112. What change is observed at anode during electrolysis of aqueous copper(II)
sulphate using a platinum electrode?
a)loss in mass
b)pink solid deposit
c)bubbles of green gas
d)gain in mass
113. Electrolysis of acidified water is an example of ------------ reaction.
a. Oxidation
b. Reduction
c. Redox
d. Decomposition
114.If the fork is to be electroplated with silver metal, what electrolyte should be
used?
a. Molten silver chloride
b. Aqueous silver nitrate
c. Sodium argento cyanide
d. Nickel sulphate solution
115. Match the column correctly.

Column I Column II

i. cation A.negatively charged ion

ii.anion B. loss of electrons

iii.oxidation C .gain of electrons

iv.reduction D .positively charged ion

a. i-a,ii-d,iii-b,iv-c
b. i-d,ii-a,iii-c,iv-b
c. i-d,ii-a,iii-b,iv-c
d. i-a,ii-d,iii-c,iv-b
116. Select the incorrect statement regarding strong electrolyte.
a. Good conductor of electricity
b. They partially dissociate in fused or molten state
c. These solution contain free ions
d. Aqueous copper sulphate is strong electrolyte
117. Select the correct statement regarding weak electrolyte.
a. Good conductor of electricity
 b. They partially dissociate in fused or molten state
c. These solution contain free ions
d. Aqueous copper sulphate is strong electrolyte
118. A salt which is a weak electrolyte.
a. Lead acetate
b. Silver nitrate
c. Lead bromide
d. Copper sulphate
119. A base which is a weak electrolyte
a. Potassium hydroxide
b. Lithium hydroxide
c. Sodium hydroxide
d. Ammonium hydroxide
120. An inert electrode and an active electrode
a. Platinum, carbon
b. Carbon, copper
c. copper , silver
d. Silver , nickel
121. The ion which will be discharged easily at cathode:-
2+ 2+ 2+ 2+
Mg , Zn , Ca ,Cu
2+
a. Ca
2+
b. Zn
2+
c. Cu
2+
d. Mg
122. Select the correct statement.
a. Oxidation of non metal , occurs at cathode
b. Reduction of metal , occurs at cathode
c. Oxidation of metal , occurs at anode
d. Reduction of non metal , occurs at anode
123.Which is the correct electrochemical series?
a)Na, Al, Fe, Mg, Zn
b)Mg, Fe, Zn, Na, Al
c)Na, Mg, Al, Zn, Fe
d)Fe, Zn, Na, Mg, Al

124. Which of these is an anion?

a)Cl-
b)Cl2
c)Na
d)Na+
125.Which of these is a cation?
a)Cl-
b)Cl2
c)Na
d)Na+

126.Which ions are present in molten magnesium bromide?

a)Mg+ and Br-
b)Mg2+ and Br-
c)Mg2+ and Br2-
d)Mg2+ and Br2-

127. What are the products when molten sodium oxide is electrolysed?
a)Na2 and O2
b)Na+ and O2-
c)Na and O
d)Na and O2

128. Which ions are present in sodium chloride solution?

a)Na+ and Cl- only
b)Na and Cl2
c)Na+, Cl-, H+ and OH-
d)Na, Cl2 and H2O

129. In electrolysis of concentrated sodium chloride solution,the ions that are chosen to
be discharged at anode are .................. ions and the product formed is ................
a)chloride ions,chlorine gas
b)sodium ions, sodium metal
c)hydrogen ions,hydrogen gas
d)hydroxide ions,oxygen gas

130. Oxidation is loss of electrons. Where does oxidation take place during electrolysis?
a)At anode
b)In the electrolyte
c)At the circuit
d)At cathode

131. Which is the correct half equation for the anode during the electrolysis of molten
lead bromide?
a)Pb2+ + 2e- --> Pb (l)
b)2Br - + 2e - --> Br2 (g)
c)Pb2+ --> Pb (l) + 2e-
d)2Br - --> Br2 (g) + 2e -

132- The diagram shows the electroplating of a steel object. A student made the
following statements.
1 The object turns a reddish-brown colour.
2 The copper sulfate solution changes to a paler blue colour.
3 The copper electrode becomes smaller.
Which statements are correct?
a)1, 2 and 3
b)1 and 2 only
c)1 and 3 only
d)2 and 3 only

133 - 136 . Choose the odd one out and mention the criteria of the group.
133. carbonic acid, acetic ,oxalic, kerosene
a. Carbonic acid [ strong electrolyte
b. Kerosene [ weak electrolyte ]
c. Carbonic acid [ weak electrolyte]
d. Kerosene [ non electrolyte]
134. Alcohol, sodium chloride, sugar solution, carbon disulphide.
a. Carbon disulphide [non electrolyte]
b. Sodium chloride [non electrolyte]
c. Carbon disulphide [weak electrolyte]
d. Sodium chloride [weak electrolyte]
135. Sodium chloride, sodium sulphate, sodium nitrate, sulphuric acid
a. Sodium nitrate [strong electrolyte salt]
b. Sodium nitrate [strong electrolyte acid]
c. Sulphuric acid [strong electrolyte salt]
d. Sulphuric acid [strong electrolyte acid]
136. Copper , platinum, silver, nickel
a. Silver [active electrode]
b. Nickel [inactive electrode]
c. Copper [active electrode]
d. Platinum [inactive electrode]
137 - The condition that is most appropriate for electroplating :-
a. Low current for longer time
b. Article to be electroplated is placed at anode
c. A.C. current is used
d. Metal to be plated on article is placed at cathode
138 - In electrorefining of silver.A is the anode, and B is the cathode, respectively,are
a. Pure silver,impure silver
b. Impure silver, pure silver
c. Pure silver, pure silver
d. Impure silver, impure silver
139 - which of the following species will be deposited at the cathode on the electrolysis
of an aqueous solution of potassium bromide?
a. Potassium
b. Hydrogen molecule
c. Bromine molecule
d. Oxygen molecule
140 - For electroplating a brass jug with copper, the anode must be made of
a. Zinc
b. Copper
c. Nickel
d. Platinum
141 - In electrolysis of an aqueous solution of sodium sulphate, the gas collected at
anode will be:-
a. Hydrogen
b. Sulphur dioxide
c. Sulphur trioxide
d. Oxygen
142 - which of the following equations truly represents the anode reaction in nickel
plating?
2+
a. Ni + 2 e ---> Ni
2+
b. Ni ----> Ni +2e
-
c. 4OH ----> O2 + 2 H2O + 4 e
2-
d. SO 4 ---> SO2 + O2 + 2 e
143 - which of the following combinations is true for carrying out electroplating of an
object?
a. Direct and large current
b. Alternating and small current
c. Alternating and large current
d. Direct and small current
144 -- During the process of electrolytic refining of copper, some metals present as
impurity settle as ‘anode mud’. These are:
a. Pb and Zn
b. Sn and Ag
c. Fe and Ni
d. Ag and Au
145 - carbon rods used as electrodes are made up of.
a. Graphite
b. Coke
c. Diamond
d. Platinum
146- In the electroplating process an external voltage is applied across a pair of
electrodes, causing:
a. a current to flow through an electrolyte
b. An electroplate to form on an electrolyte
c. An alternating voltage in a magnetic chemical
d. a chemical to produce a negative voltage on a positive electrode

147. If a small amount of an acid, alkali or salt is added to water, it can become:

a. a very good insulator

b. quite a good conductor
c. a semiconducting diode
d. an electro-positive acceptor

148 - Two copper plates that are immersed in a solution of water and copper sulphate.
A voltage has been applied to the two electrodes, and a current is flowing. This current
will cause the, copper sulphate to break down into:

a. negative copper ions and negative sulphate ions

b. negative copper ions and positive sulphate ions
 c. positive copper ions and positive sulphate ions
d. positive copper ions and negative sulphate ions

149 - The following equation shows the shows the action if copper sulphate is dissolved
in water and a current passed through it.

2+ 2-
CuSO4 ⇆ Cu + SO4

a. recombination can take place to form neutral molecules of copper sulphate

b. the negative ions in the solution have a deficiency of electrons
c. copper can be split from the SO4 sulphate radical in the electrode
d. copper sulphate molecules will always return a positive charge to the electrode

150. Look at the following diagram:

The drawing shows the basic requirements of an electroplating bath. In the drawing,
the:
a. copper electrode will be zinc plated
b. zinc spoon will go into solution in the electrolyte
c. copper electrode will be plated with sulphate
d. zinc spoon will be copper plated

Answer Key
1.a
2.a
3.c
4.d
5.a
6.b
7.c
8.d
9.b
10.a
11.b
12.c
13.c
14.b
15.b
16.c
17.a
18.c
19.a
20.c
21.c
22.c
23.c
24.b
25.c
26.b
27.c
28.d
29.d
30.c
31.a
32.b
33.b
34.d
35.d
36.b
37.c
38.c
39.c
40.a
41.b
42.a
43.b
44.d
45.a
 46.d
47.a
48.d
49.d
50.d
51.a
52.d
53.a
54.b
55.d
56.c
57.b
58.c
59.c
60. b
61. A
62.c
63.d
64. b
65. c
66.a
67. B
68. C
69.d
70. A
71. B
72. B
73. C
74. A
75. C
76.b
77.c
78.b
79.c
80.a
81.c
82.c
83.d
84.b
85.d
86.d
87.c
88.a
89.d
90.b
91.d
92.a
93.c
94.d
95.c
96.b
97.d
98.b
99.b
100.b
101. D
102. C
103. C
104. D
105.d
106. B
107. A
108. D
109.d
110. C
111. C
112. A
113. C
114.c
115 - c
116- b
117 - b
118 - a
119 - d
120 - b
121 - c
122 - b
123 - c
124 - a
125- d
126-b
127 - d
128 - c
129 - a
130 - d
131 - d
132 - c
133 - b
134 - b
135 - c
136 - d
137 - a
138 - b
139 - b
140 - b
141 - d
142 - b
143 - d
144 - d
145 - a
146 - a
147 - b
148 - d
149 - a
150 - d