Electro chemistry
Multiple choice Questions:1) In an electro chemistry cell the electrical energy is
obtained at the cost of
a) Mechanical energy
b) internal energy
c) chemical energy
d) Thermal energy
Ans: (c)
2) The device used to bring about non-spontaneous red px
reactions by supplying electrical energy is called
a) electrochemical cell
b) electrolytic cell
c) dry cell
d) De
Ans: (b)
3) Some statements are given below
a) The electrolytic conduction is due to the migration
of ions through the electrolyte
b) The postage of electric current through the
electrolyte leads to the chemical changes
c) Electrolysis is a spontaneous redox reaction.
d) Sodium chroride carries electricity only in its
aquarous solution.
(Among the above the correct statements are)
Ans : (c)
4) One & araday of electricity liberates the amount of ions
which is equal to its
a) molecular weight
b) atomic weight
c) equivalent weight
d) none of these
Ans: (a)
5) The atomic weight of Cu is 64. The weight Cu liberated
from CuSo4 solution by passing a current of 0.965
ampere for 1000 seconds would be
a) 0.64 g
b) 0.64 kg
c) 0.32 kg
d) 0.32 x 103 kg
Ans : (a)
6) Some statement are given below
a) The weight of on ion liberated during electrolysis
is directly proportional to the quantity of current
passed.
b) Coulomb is the product of current in ampere and
time.
c) the weight of substance formed at the electrode
by the same amount of electricity is proportional
to the equivalent weight of that substance
d) The minimum weight of that substance which can
be obtained during electrolysis is its
electrochemical equivalent
(Among the above the false statement are a, b & d)
Ans: (c)
7) The atomic weight of Al is ‘X’ the electrochemical
equivalent of Al in the solution of Aluminium sulphate will
be
a)3X/F
b) X/3F
c) 2X/F
d) X/F
Ans : (b)
8) The current of 5000 MA is passed through a solution for
10 seconds. The no. of coulombs passed are
a) 50000
b) 500
c) 5000
d) 50
Ans : (d)
9) The No. of coulombs required to liberate 0.224 dm3 of
chlorine at 00C @ 1 atm (NTP) pressure is
a) 2 X 965
b) 965/2
c) 965
d) 9650
Ans:
(a)
10) The No. of coulombs required to liberate 1.12 dm3 of H2
at 2730C and 2 atm pressure is
a) 2 X 9650
b) 9650
c) 4 X 9650
d) 965
Ans:
(c)
11) The volume of O2 at STP by the passage of 2 for a day
of electric charge through acidulated water is
a) 22.4 Lit.
b) 5.6 Lit.
c) 11.2 Lit.
d) 2.24 Lit.
Ans:
(c)
12) The volume of H2 liberated at 2730C and at atm
pressure by the passage of 1 Euroaday of electricity
through HCL solution is
a) 11.2 dm3
b) 22.4 dm3
c) 44.8 dm3
d) 5.6 dm3
Ans:
(b)
13) 2 X 10-3 kg of on element i.e. deposited by passing 2A
current for 16 min and 5 second through a solution.
The equivalent weight of the element is
a) 100
c) 25
Ans:
(a)
b) 50
d) 200
14) The chemical equivalent of the element A,B and C are
4,12 and 20 respectively. The weight of A, B and C
liberated by 1000 coulomb will be in the rating of
a) 5 : 3 : 1
b) 1 : 3 : 5
c) 1 : 1 : 1
d) 1 : 2 : 2
Ans :
(b)
15) The electro chemical equivalent of metal A and B are in
the ratio of X:Y. If a given quantity of electricited
deposit & weight of A, the weight of B deposited by the
same quantity of electricity would be
a) WY/X
b) WY/Wxg
c) Wg.
D) WX/Yxg
Ans: (a)
16) The atomic weight of elements x and y are in the ratio
of 1:2 coulombs deposit equal weights of these two
elements. Then ik valency of x is 2 that of y is
a) 2
b) 1
c) 4
d) 3
Ans : (c)
17) If the current of x ampere is passing through a solution
for t min. The number faradays passing are
a) 60 xt
b) xt
c) 60xt / 96500
d) xt / 96500
Ans : (c)
18) One horse power is equal to
a) 1000 J
b) 647 watt
c) 746 Watt
d) 1000 KJ
Ans:
(c)
19) Some statement are given below
A) Joule is the unit of work
B) Faraday is the unit of electric current
C) Watt is the work performed at the rate of 1 Joule
per second
D) Volt = Ohm x Ampere
Among the above the true statements are
a) only A & C
b) only A,B & D
c) only A,C & D
d) all
Ans : (c)
20) The cell reaction of the Daniall cell in the standard state
can be correctly represented as
a) Zn (s) + Cu2- (aq)  Zn2+ (aq) + Cu (s)

b) Zn (s) + Cu2- (aq) (1M)  Zn2+ (aq)(1M) + Cu (s)

22+
c) Zn (s) + Cu  Zn + Cu (s)

2d) Zn (aq)(1M) + Cu (s)  Zn (s) + Cu2+ (aq)(1M)

Ans :
(b)
21) During the working of the Daniell cell, which of the
following happens
a) The size of the Zn rod remains same but the blue
colour of CuSo1 solution becomes faint
b) The size of the Zn rod is reduced and the blue
colour of CuSo4 solution becomes faint.
c) The size of the Zn rod reduced but there is no
change in the intensity of colour of the CuSo4
solution.
d) The size of the Zn rod as well as the intensity of
the colour of CuSo4 solution remain unchanged.
Ans:
(b)
22) Some Statements are given below
A) In an electrochemical cell oxidation takes place at
anode.
B) In an electrochemical cell reduction takes place at
cathode.
C) In takes Daniell cell the Cu electrode grows in size
during the working of the cell.
D) The salt bridge maintains electrical neutrality of the half
-cell ionic solutions.
Among the above the wrong statement is
a) Only B
c) Only A
Ans : (d)
b) Only C
d) None
23) 25. In the cell; Pt, O2 (g)| OH- || Cl- | Cl2 (g) Pt, the
anode half cell reaction is
a) OH  ½ O2 + ½ H2 + e
b) 2OH  O2 + H2 + 2e
c) 2OH  ½ O2 + H2O + 2e
d) ½ O2 + H2O + 2e 2OH
Ans : (c)
24) In a saturated calomel electrode the KCl solution is
saturated with
a) Only KCl
b) Only calomel
c) Both KCl and calomel
d) None
Ans : (c)
25) The potential of a calomel electrode depends on
a) concentration of KCl only
b) temperature only
c) both, the concentration of KCl and temperature
d) its construction.
Ans : (c)
26) The standard reduction potential of the metal A, B and
C are in decreasing order. Which of these will always
behave as the anode when coupled with the other two
separately to form a cell ?
a) A
b) B
c) C
d) can not be predicted
Ans : (c)
27) The S.O.P values of metals A, B and x and y
respectively. If x > y, the standard EMF of the cell
containing these electrodes would be
a)
b)
c)
d)
Ans:
(a)
x–y
y–x
x+y
unpredictable
28) The metals X, Y and Z follow one another in the same
order in the E.M.F. series of S.O.P. On this basis
some statements are made below
A) The ease of oxidation is in the order X > Y > Z
B) The reducing power decreases in the order X > Y > Z
C) X will displace Y and Z from their solutions.
D) The maximum E.M.F. if the cell will be obtained by using
X and Y as electrodes.
Among the above the correct statements are
a) Only A, B & D
b) Only A, C & D
c) Only A, B & C
d) All
Ans : (c)
29) When electricity is passed through a solution of AlCl3,
13.5 g of Al (At. Wt. 27) is deposited. The number of
Faradays passed through the solution must be
a) 0.5
c) 1.5
Ans: (c)
b) 1
d) 2
30) Faraday’s laws of electrolysis are concerned with
a) equivalent weight
b) atomic weight
c) molecular weight
d) atomic number
Ans : (a)
31) Which of the following will decompose by passing
current through its aqueous solution ?
a) glucose
c) urea
Ans : (d)
b) ethanol
d) silver nitrate
32) In electrolysis, oxidation takes place at
a) anode
b) cathode
c) both, at the anode and at the cathode
d) the surface of the solution
Ans : (a)
33) 41. No. of faradays required to generate one gm atom
of Mg from MgSO4 solution is
a) 1
c) 3
Ans : (b)
b) 2
d) 4
34) During electrolysis of NaCl, the reaction Na+ +e-  Na
takes place at
a) anode and called electronation.
b) anode and called reduction.
c) cathode and called oxidation.
d) cathode and called electronation.
Ans: (d)
35) The atomic weight of Al is 27. The weight of aluminium
deposited by a passage of 5 Faradays through
aqueous Al2 (SO4)3 solution will be
a) 27 g.
b) 9 g.
c) 45 g.
d) 36 g.
Ans : (c)
36) During the electrolysis of the aqueous solution of NaCl
the reaction taking place at anode is
a) oxidation of sodium ions.
b) oxidation of chloride ions.
c) reduction of chloride ions.
d) reduction of sodium ions.
Ans: (b)
37) Weight of copper deposited by the passage of 2
Faradays of electricity through the aqueous solution of
cupric ions is equal to its
a) atomic weight
b) molecular weight
c) electrochemical equivalent weight
d) equivalent weight
Ans: (a)
38) The number of electrons involved in the reaction by
passing one Faradays an electrolyte is
Ans: (c)
a) 96500
b) 12 X 1023
c) 6 X 1023
d) 96500 X 6 X 1023
39) The number of coulombs equal to one Faraday is
a) 95600
c) 95500
Ans: (b)
b) 96500
d) 93600
40) During the electrolysis of NaCl solution the gas
liberated at cathode is
a) Cl2
c) O2
Ans: (b)
b) H2
d) H2 and O2
41)
The amount of an ion discharged during electrolysis
in not directly proportional to
a) Time
b) strength of current
c) equivalent weight
d) concentration of solution
Ans: (d)
42) Faraday’s laws of electrolysis will fail if
a) temperature is changed
b) inert electrodes are used
c) concentration of the solution is changed
d) none of these
Ans: (d)
43) The unit of electrochemical equivalent is
a) gram/sec
c) gram/coulomb
Ans: (c)
b) gram/ampere
d) gram/Faraday
44)
The atomic weight of Al is 27. The ECE of Al in AlCl3
solution is
a)
27
96500
c) 96500
27
Ans: (d)
b) 27  3
96500
d)
9
96500
45) The charge needed to liberate 0.5 gm atomic weight of
a divalent element is
a) 96500 C
c) 2 Faraday
Ans: (a)
b) 48250 C
d) 5 Faraday
46) The molten electrolyte conducts electricity due to the
presence of
a) free electrons
c) free molecules
Ans: (c)
b) free ions
d) free atoms
47) A solution of electrolyte in water, when electrolysed,
liberated H2 at the cathode and Cl2 at the anode. The
electrolyte must be
a) H2SO4
c) NaCl
Ans: (c)
b) CuCl2
d) Na2SO4
48) In electrolysis of a fused salt, the weight of a substance
liberated at the electrode is independent of
a) temperature
b) current intensity
c) electrochemical equivalent of ion
d) time for electrolysis
Ans: (a)
49) A certain current liberates 0.504 x 10-3 kg of H2 in a
certain time. The weight of copper (at wt. 63.6)
liberated by the same current in the same time from
CuSO4 Solution is
a) 15.9 kg
c) 31.8 x 10-3
Ans: (d)
b) 63.6 kg
d) 15.9 x 10-3 kg
50) Current is passed through the solutions of silver nitrate
and copper sulphate connected in series. The weight
of Ag (At wt. 108) deposited in 10.8 g. The weight of
Cu (At wt. 64) deposited will be
a) 6.4 g
c) 1.6 g
Ans: (b)
b) 3.2 g
d) 10.8 g
51) When the same quantity of electricity is passed through
different electrolysis the weights of elements deposited
are in the ratio of their
a) At. No.
c) Sp. gravity
Ans: (d)
b) At. Wt.
d) ECE
52) 3.5 Faradays of electricity are passed through a
solution of CuSO4. The no. of gm. Equivalent of Cu
deposited will be
a) 3.5
c) 7
Ans: (a)
b) 1.75
d) 1
53) A current of “ I ” amperes is passed through the
solution of an electrolyte for time “ t min”, when m g of a
substance is liberated at the electrode. The ECE of the
substance is equal to
a)
c)
m
t
m
60It
Ans: (d)
b)
d)
IT
m
It
60m
54) The amount of Ag (at. Wt 108) deposited by the
current, which deposits 3.2 of O2 is
a) 10.8 g
c) 21.6 g
Ans: (b)
b) 43.2 g
d) 3.2 g
55) The given amount of current is passed through the cells
placed in series containing the solutions of AgNO3,
NiCl2 and CrCl3. The amounts of Ag (at. Wt. 108), Ni
(at. wt. 60) and Cr (at. Wt. 51) liberated will be in the
ratio of
a) 108:60:51
c) 108:20:25.5
Ans: (d)
b) 108:30:25.5
d) 108:30:17
56) The reference electrolyte is made from
a) ZnSO4
c) Hg2Cl2
Ans: (c)
b) CuSO4
d) HgCl2
57)
The S.O.P. values of metals are in the following order :
Zn>Cd>Ni>Cu>Ag. On the basis of this, some
statements are made below
A) A solution of CuSO4 is stirred with Zn rod when
the blue colour of the solution fades.
B) Cu displaces Ni from NiSO4 Solution.
C) Maximum EMF of the cell is obtained by using Zn
and Ag as electrodes.
D) Ag will displace all the others from their solutions.
Then from the above
a) Only D is false
c) A and D are true
Ans: (b)
b) B is false
d) B and C are true.
58)
When a copper wire is dipped in a solution of AgNO3,
the colour of the solution becomes blue because
copper
a) is oxidized to Cu2+ which enter the solution.
b) is reduced to Cu+
c) enters the solution as copper atoms.
d) cannot displace Ag from the solution.
Ans: (a)
59)
The S.R.P. of Mg and Cu are – 2.30 V and +0.337 V
respectively, then which of the following is wrong?
a) Mg can displace H2 from acids.
b) Mg can displace Cu from CuSO4 Solution.
c) Cu will displace H22 from acids.
d) Cu can not displace Mg from MgCl2 Solution.
Ans: (c)
60) A depolariser used in a dry cell is
a) ammonia chloride
b) Manganese dioxide
c) Potassium chloride
d) saw dust
Ans: (b)
61) The colourless aqueous solutions of the following salts
are placed in separate test tubes and a Cu strip
immersed in each of them. Which solution will finally
turn blue?
a) Pb(NO3)2
c) AgNO3
Ans: (c)
b) Zn(NO3)2
d) Cd(NO3)2
62) If an iron rod is placed in a solution of copper sulphate
a) copper will precipitate out.
b) iron will precipitate out.
c) iron and copper both will dissolve.
d) No reaction will take place.
Ans: (a)
63) A calomel electrode is
a) standard hydrogen electrode
b) Reference electrode
c) Platinum electrode
d) Mercury electrode
Ans: (b)
64) A decinormal calomel electrode contains
a) N / 10 solution Hg2Cl2
b) 1 N solution of KCl
c) 1 N solution Hg2Cl2
d) N / 10 solution KCl
Ans: (d)
65)
In an aqueous solution, H2 will not reduce
a) Fe3+
b) Cu2+
c) Zn2+
d) Ag+
Ans: (c)
66)
The electric charge for the deposition of one
equivalent of a substance, during electrolysis is
a) One ampere for 9650 seconds.
b) 96500 ampere for one hour.
c) One ampere for one hour.
d) Charge on one mole of electrons.
Ans: (d)
67)
Following are the actual observations made in the
laboratory.
i) C does not react with the solution of salt of B
ii) B dissolves in the solution of the salt of A
iii) A does not react with the solution of the salt of C
The reducing power of these metals is in the order
a) A > B > C
b) C > B > A
c) B > C > A
d) B > A > C
Ans: (c)
68)
The standard reduction potentials of A, B and C are
- 0.76 V, + 0.80 V and + 0.34 V respectively. The
reducing power decreases in the order
a) A > B > C
b) C > B > A
c) A > C > B
d) B > C > A
Ans: (c)
69)
The standard potentional for the reaction,
2H+ (ag) + 2e-  H2 (g), is
a) 0 V
b) 1 V
c) – 1V
d) none of these
Ans: (a)
70) If a salt bridge is removed from between the two half
cells, the EMF
a) drops to zero
b) does not change
c) decreases gradually
d) increases gradually
Ans: (a)
71) During the charging of lead storage battery, the
reaction at anode is
a) Pb2+ + SO2-4  PbSO4
b) PbSO4 + H2O  PbO + SO2-4 + 2H+
c) Pb  Pb2+ + 2ed) Pb2+ + 2e-  Pb
Ans: (d)
72) The metal which can not displace H2 from acid is
a) Hg
b) Ba
c) Al
d) Pb
Ans: (a)
73) 3 Faraday of electricity is passed through electrolytes
containing Al3+, Na+ and Cu2+ ion. The amounts of
Al, Cu and Na liberated at the cathode will be in the
molar ratio of
a) 3:2:1
b) 1:2:3
c) 2:3:6
d) 6:3:2
Ans: (c)
74) A cells A and B contain aqueous acidified ferrous
chloride and ferric chloride respectively. The weights of
iron deposited by the same quantity of electricity in the
cells A and B are in the ratio of
a) 1:1
b) 3:1
c) 2:1
d) 3:2
Ans: (d)
75) The current liberates 112 ml H2 gas at STP in 965
seconds. The current passed in ampere is
a) 1
b) 0.5
c) 0.1
d) 2
Ans: (a)
76) The ECE of metal is “ E ”. The amount of the metal
deposited by the passage of 500 mA current through
the solution for 4 minutes will be
a) 2000E g.
b) 1200E g.
c) 120E g.
d) 2E g.
Ans: (a)
77) In a compound “x” g. of the metal combines with 35.5 g.
of chlorine. The weight of the metal liberated by the
passage of “y” coulomb of electricity through the
solution of the compound will be
a)
xy
g
96500
c) 96500
y
Ans: (d)
b)
d)
g.
xyg .
96500y
g
x
78) “W” g. of a metal is deposited by a current o “I” ampere
for “t” minutes. The equivalent weight of the metal is
a)
w
60IT
c) 96500It
Ans: (b)
96500w
b)
60ItIt
60
d) 60WIt
79) The standard EMF of a Daniell’s cell is 1.10 V. The
EMF of the cell at 250 c, when 0.1 M Cu2+ and 0.1 M
Zn2+ solutions are used, is
a) 1.10 V
b) – 1.10 V
c) 0.110 V
d) – 0.110 V
Ans: (a)
80) The charge, in Faraday on 0.25 mole of electron is
Ans: (b)
a)
F
c)
F
4
b)
d)
F
2
96500F
81) Zn displaces silver from AgNO3 Solution, because
a) Zn is higher up in EMF series than Ag
b) Reduction potential of Zn is more than that of Ag
c) Zn reacts with AgNO3 Solution.
d) Oxidation potential of Zn is more than that of Ag
Ans: (d)
82) The Pt. foil in a hydrogen electrode is coated with
platinum black because the latter
a) Increases
increases its surface area and minimises
polarisation.
b) is a good conductor.
c) prevents the electrode from damage.
d) maintains better electrical contact.
Ans: (a)
83) The number of equivalents of Mn+ ions liberated by the
passage of n Faraday of charge through the solution of
Mn+ is
a)
F
b)
nn
c)
1
n
d)
n
F
Ans: (b)
84) Anode is an electrode at which
a) electrons flow out of an electrolyte.
b) electrons flow into the electrolyte.
c) reduction takes places.
d) cations are converted to atoms.
Ans: (a)
85) The EMF of an electrochemical cell must be measured
by a null method to avoid
a) heat generation
b) corrosion at the electrodes
c) changes in electrolyte concentration
d) the stoppage of cell reaction
Ans: (c)
86) Coulomb is a unit of
a) current
b) energy
c) work
d) charge
Ans: (d)
87) Zinc displaces copper from the solution of the latter’s
salt because
a) atomic number of Zinc is more than that of copper
b) Zinc has more positive standard reduction
potential than copper.
c) Zinc has more positive standard reduction
potential than copper.
d) Zinc salt is more soluble in water than copper salt
Ans: (d)
88) During electrolysis of water the volume of O2 liberated
is 2.24 dm3. The volume of hydrogen liberated, under
same conditions, will be
a) 2.24 dm3
b) 1.12 dm3
c) 4.48 dm3
d) 0.56 dm3
Ans: (c)
89) The element which can displace lithium from the
solution is
a) Mg
b) Zn
c) H2
d) None of these
Ans: (d)
90) The EMF of the cell can not be measured accurately by
a voltmeter because,
a) there are concentration changes during
measurement
b) voltmeters are not very sensitive.
c) the voltmeter changes the cell reaction.
d) cations are converted to atoms.
Ans: (a)
91) During the electrolysis of aqueous sodium chloride the
product obtained at the cathode is
a) sodium metal
b) chlorine
c) oxygen
d) hydrogen
Ans: (d)
92) A current of 5 ampere was passed through SnCl2
solution for 10 min and a current of 10 ampere through
a solution of SnCl4 for 5 min. The amount of tin
deposited in the 1st and 2nd case are x g and y g.
respectively, then
a) x = y
b) 2x = y
c) 2x = 3y
d) x = 2y
Ans: (d)
93) In the solution of an electrolyte the current is carried by
a) electrons
b) cations and anions
c) molecules
d) atoms
Ans: (a)
94) Which of the following statements is correct ?
a) During electrolytic dissolution, the number of
cations and anions obtained are always equal.
b) The electrolyte dissociation leads to reduction in
number of particles in the solution.
c) The cations and anions do not reunite to give
back neutral molecules.
d) The number of positive and negative ions are
equivalent
Ans: (d)
95) Some statement are given below
A) Electrolysis is a non-spontaneous redox reaction.
B) ECE of an ion is its weight liberated by one Faraday of
electricity.
C) One device to convert electrical energy to chemical
energy is called Voltaic cell.
D) If the solution pressure of the metal is greater than the
osmotic pressure of cations, the metal electrode
becomes negatively charged.
Among the above
a) Only B is false
b) only C is false
c) B,C and D are false
d) B and C are false
Ans: (d)
96) The standard potential of an electrode is its potential
when the concentration of the salt solution is
a) 1 M at 25 K
b) 1 N at 25 K
c) 1 N at 298 K
d) 1 M at 298 K
Ans: (d)
97) For the cell reaction,
Cd(s) + 2 Ag+ (0.5 M)  Cd2+(0.25M) +2Ag (s)
Ans: (a)
a)
1.20 V
c)
298
1.20 X
V
303
b)
1.20 X
303
V
298
303
[
1
.
20

(
0
.
0591
x
)]V
d)
298
98) Faradays laws of electrolysis are related to the
a) atomic number of the cation.
b) atomic no of the anion.
c) equivalent mass of the electrolyte.
d) speed of the cation
Ans: (c)
99) When a lead storage battery is discharged
a) SO2
b) lead sulphate is consumed
c) lead is formed.
d) sulphuric acid is consumed
Ans: (d)
100) If , I = current in ampere, t = time in seconds, Q =
charge passing in coulomb, then which of the
following expressions is correct ?
a) I = Qt
b) I = Q / t
c) I = 1 / Qt
d) I = t / Q
Ans: (b)
101) In an electrolytic cell, which of the following is NOT
true?
a) Cathode is negative terminal.
b) Cathode is positive terminal.
c) Reduction occurs at cathode.
d) Electrons enter into cathode from the external
cell.
Ans: (b)
102) The density of Cu is x g cm-3 and its equivalent
weight is E. The quantity of electricity, in Faraday
needed to plate an area of 10 cm x 10 cm to a
thickness of 10-2 cm., using CuSO4 solution is
a) E / x
b) 96500 E / x
c) 96500x / E
d) x / E
Ans: (d)
103) When the lead accumulator is charged
a) sulphuric acid is formed
b) sulphuric acid is consumed
c) lead sulphuate is formed
d) lead is consumed
Ans: (a)
104) In and electrolysis of aqueous solution of Na2SO4,
1.5 litre of oxygen was liberated at anode. The
volume of hydrogen, under similar conditions,
liberated at cathode would be
a) 0.75 litre
b) 1.5 litre
c) 3 litre
d) 12 litre
Ans: (c)
105) The quantity of the metal deposited at the cathode
during electrolysis depends on
a) Shape of cathode
b) concentration of electrolyte
c) only the quantity of charge passing through the
solution
d) the quantity of charge and vallancy of metal ion.
Ans: (d)
106) In the electrolysis of acidulated water a total of 3 mole
of gases are evolved. The amount of water
decomposed would be
a) 3 mole
b) 2 mole
c) 6 mole
d) 4 mole
Ans: (b)
107) The atomic weight of a metal is 64. During
electrolysis of aqueous solution of its salt 3.2 g it are
deposited by the passage of 1/10 Faraday. The
valency of the metal ion is
a) 1
b) 2
c) 3
d) 4
Ans: (b)
108) In acidic medium, MnO4- is converted to Mn2+. The
quantity of electricity in Faraday required to reduce 0.5
mole of MnO4- to Mn2+ would be
a) 2.5
b) 5
c) 1
d) 0.5
Ans: (a)
109) The metal which can not be obtained by the
electrolysis of the aqueous solution of its salt is
a) Ag
b) Cr
c) Na
d) Cu
Ans: (c)
110) The standard potentials for the following half-cell
reactions are given against each:
Zn2+ (ag) +2e-  Zn (s) ; - 0.763 V

2H+ (ag) + 2e-  H2 (g) ; 0.000 V

Ni2+ (ag) + 2e-  Ni (s) ; - 0.28 V

Fe3+ (ag) + e-  Fe3+ (ag) ; 0.770 V

Among these, which is the strongest reducing agent ?
a) Fe3+ (ag)
b) H2 (g)
c) Ni (s)
d) Zn (s)
Ans: (d)
111) In the conventional representation of an
electrochemical cell, which of the following is correct ?
a) Right electrode is a positive terminal
b) Left electrode is cathode
c) Right electrode is anode
d) Left electrode is a positive terminal
Ans: (a)
112) In the dry cell,
a) the graphite rod is negative terminal
b) the ammonia gas accumulates in the cell during
its working.
c) the Zn vessel is a negative terminal.
d) the cell reaction involves the complex formation of
Zn with MnO2
Ans: (c)
113) In the lead – storage cell
a) the cell reaction can not be reserved by any
method.
b) the EMF does not depend on the density of the
H2SO4 solution.
c) during charging the SO42- ions are liberated only
at anode
d) The spongly lead electrode behaves as –ve
terminal when the current is drawn from the cell.
Ans: (d)
114) Some statements are given below
A) Reduction takes place at cathode in both, galvanic as
well as electrolytic cells.
B) Cathode is a negative terminal in both, galvanic and
electrolytic cells.
C) Anode is a negative terminal in an electrolytic cell but a
positive terminal in a galvanic cell.
D) Oxidation occurs at anode in a galvanic cell whereas
reduction occurs at anode in an electrolytic cell.
Amongst the above the false statements are
a) only A, B and C
b) only B, C and D
c) only B and D
d) all the four
Ans: (b)
115) The S.O.P. of metals A and B are 0.40 V and - 0.77 V
respectively. These two metals are used as
electrodes in a cell. Which of the following statements
is correct for the cell ?
a) A serves as cathode
b) B serves as anode
c) Reduction occurs at B
d) E0 for the cell is 0.37 V
Ans: (c)
116) If E0 (Ca2+ / Ca) = -2.87 V and E0 (Sn2+ / Sn4+) = -0.15
V, the best reducing agent would be
a) Ca2+
b) Ca
c) Sn2+
d) Sn4+
Ans: (b)
117) The S.R.P. of A, B, C and D are – 0.40 V, -1.34 V,
0.80 V and 0.77 V respectively. Which of the
following will take place ?
a) D is displace A and C from their salt solutions.
b) A will displace B but not D from their salt
solutions.
c) B will displace all others from their salt solutions.
d) C will displace all others from their salt solutions.
Ans: (c)
118) Some statements are given below
A) Cu metal can reduce Fe2+ in acidic medium.
B) Sodium metal can not be obtained by the electrolysis
of aqueous NaCl
C) In the Daniell cell electrons flow from Zn to Cu
electrode through the external circuit
D) Platinum wire in the calomel electrode is necessary
for the chemical reaction to take place.
Among the above, the false statement(s) is / are
a) only D
b) only B and C
c) only A and D
d) only A, B and D
Ans: (c)
119) Which one of the following statements is false ?
a) The standard potential of hydrogen electrode is
zero at all conditions of temperature and
pressure.
b) The calomel electrode is reversible with chloride
ions
c) Reference electrode is that whose potential is
fixed under given conditions.
d) In a calomel electrode, as the concentration of Clions in the solutions increases, the reaction
potential decreases
Ans: (a)
120) Some statements are given below
A) The EMF of a cell is an intensive property.
B) The cell EMF becomes half if the cell reaction is divided
by 2.
C) The external cell in the electrolysis experiment acts as a
galvanic cell.
D) The conventional value of zero potential of the standard
hydrogen half cell holds good at all temperatures.
Among the above
a) only A is true.
b) A and C are true.
c) A, B and D are false
d) only B is false.
Ans: (b)
121) The equivalent weights of the element A, B and C are
in increasing order. Their weights deposited in
electrolytic cells by the same quantity of electricity are
x, y and w respectively. Then
a) x > y > w
b) x = y = w
c) x < y < w
d) x > y < w
Ans: (c)
122) The number of Faradays required to deposit one
mole atoms of M, when a solution of its M3+ ion is
electrolyzed, is
a) 3 / 2
b) 1 / 2
c) 3
d) 3 x 96500
Ans: (c)
123) The no. of moles of Ag+, Cu2+ and Fe3+ ions
deposited by 2 Faradays of electricity would be in the
ratio of
a)1:2:3
b) 1:1:1
c) 3:2:1
d) 6:3:2
Ans: (d)
124) In electrolysis the mass of ion discharged is not
proportional to
a) time
b) quantity of electricity
c) resistance of solution
d) Equivalent wt. of ion
Ans: (c)
125) Among the following, the oxidation potential is
maximum in case of
a) NCE
b) DCE
c) SHE
d) SCE
Ans: (d)
126) A cell involves the reaction,
Sn(s) + 2Aq+ (aq)  Sn2+ (aq) + 2Aq (s).
The EMF of the cell will increase by
a) increase in size of Ag electrode
b) increase in concentration of Sn2+ ions
c) decrease in concentration of Ag+ ions
d) increase in concentration of Ag+ ions
Ans: (d)
127) In the salt bridge, KCl is used because
a) it is an electrolyte
b) it is a good conductor of electricity
c) The transport number of K+ and Cl- are nearly
equal
d) it is readily soluble in water
Ans: (c)
128) During electrolysis of dilute H2SO4 solution the
amounts of substances liberated at cathode and
anode are in the ratio
a) 1:8
b) 8:1
c) 1:16
d) 16:1
Ans: (a)
129) An ion is reduced to the element when it absorbs
6 x 1020 electrons. The number of equivalents of the
element produced will be
a) 0.10
b) 0.01
c) 0.001
d) 0.0001
Ans: (c)
130) The standard EMF of the Daniell’s cell is 1.10 V. The
EMF of the cell when 0.1 M Cu2+ and 0.1M Zn2+
solutions are used will be
a) 1.10 V
b) 0.110 V
c) 1.110 V
d) 1.010 V
Ans: (a)
131) The no. of electrons associated with one coulomb are
a) 6.02 X 1021
b) 6.24 X 1018
c) 6.24 X 1015
d) 6.02 X 1016
Ans: (b)
132) The electric charge needed for electrode – position of
1 gm equivalent of a substance is
a) one ampere per sec
b) 96500 coulomb per sec
c) one Faraday per sec
d) charge on one mole of electrons
Ans: (d)
133) The charge in coulomb on Cu2+ ion is
a) 3.2 x 10-19
b) 2.3 x 10-12
c) 0.23 x 10-19
d) 1.6 x 10-19
Ans: (d)
134) A metal having negative value for its reduction
potential, when dipped in the solution of its ions, has a
tendency to
a) go into the solution
b) be deposited form the solution
c) become positively charged
d) remain neutral
Ans: (a)
135) Using same quantity of electricity, the weight liberated
will be maximum in case of
a) Na
b) Mg
c) Al
d) Cl2
Ans: (d)
136) In a Daniell’s cell, if the concentrations of Zn2+ and
Cu2+ ions are doubled, the EMF of the cell
a) is doubled
b) is reduced
c) remains same
d) becomes four times
Ans: (c)
137) Which of the following solutions can be safely stored
in a copper vessel
a) AuCl3
b) AgNO3
c) ZnSO4
d) all of these
Ans: (c)
138) The no. of moles of electrons needed to deposit one
mole of Al from Al2(SO4)3 solution would be
a) 1
b) 2
c) 3
d) 4
Ans: (c)
139) 1 x 10-2 g. atom of Ag can be oxidized to Ag+ by
using
a) 0.01 Faraday
b) 1 Faraday
c) 0.1 Faraday
d) 10 Faraday
Ans: (a)
140) The half-cell potential measures
a) the tendency of the electrode to gain or lose
electrode
b) the tendency of the cell reaction to occur
c) the current carried by the electrode
d) none of these
Ans: (b)