ELECTROCHEMISTRY 43
Conductance (Objective Questions)
Q.1 The specific conductance of 0.01 M solution of KCl is 0.0014 ohm-1 cm-1 at 25ºC. Its
equivalent conductance is :
(A) 14 (B) 140 (C) 1.4 (D) 0.14
Q.2 The equivalent conductivity of 0.1 N CH3COOH at 25 ºC is 80 and at infinite dilution 400
ohm-1. The degree of dissociation of CH3COOH is :
(A) 1 (B) 0.2 (C) 0.1 (D) 0.5
Q.3 The equivalent conductance at infinite dilution of NaCl, HCl and CH3COONa at 298 K are
126.0, 426.0 and 91.0 ohm-1 cm2 respectively. The value of equivalent conductance of acetic
acid at infinite dilution at the same temperature is :
(A) 644.0 (B) 300.0 (C) 517.0 (D) 391.0
Q.4 The specific conductance of a salt of 0.01M concentration is 1.061 × 10-4. Molar
conductance of the same solution will be :
(A) 1.061 × 10-4 (B) 1.061 (C) 10.61 (D) 106.1
Q.5 At infinite dilution of an electrolyte, the equivalent conductances of cations and anions are :
(A) independent of each other (B) interdependent of each other
(C) dependent on solvent molecules (D) dependent on charge carried by ions
Q.6 The specific conductances of a 0.1 N KCl solution at 23ºC is 0.0112 ohm-1 cm-1. The
resistance of the cell containing solution at the same temperature was found to be 55 ohm. The
cell constant will be :
(A) 0.142 cm-1 (B) 0.918 cm-1 (C) 1.12 cm-1 (D) 0.616 cm-1
Q.7 The conductivity of 0.01 mol/dm3 aqueous acetic acid at 300 K is 19.5 × 10-5 ohm-1 cm-1 and
the limiting molar conductivity of acetic acid at the same temperature is 390 ohm-1 cm2 mol-1.
The degree of dissociation of acetic acid is :
(A) 0.5 (B) 0.05 (C) 5 × 10-3 (D) 5 × 10-7
Q.8 The ionization constant of a weak electrolyte is 25 × 10-6 while the equivalent conductance of
its 0.01 M solution is 19.6 s cm2 eq-1. The equivalent conductance of the electrolyte at infinite
dilution (in 5 cm2 eq-1) will be :
(A) 250 (B) 196 (C) 392 (D) 384
Q.9 The resistance of 1 N solution of acetic acid is 250 ohm, when measured in a cell of cell
constant 1.15 cm-1. The equivalent conductance (in ohm-1 cm2 equiv-1) of 1 N acetic acid is :
(A) 4.6 (B) 9.2 (C) 18.4 (D) 0.023
Q.10 The cell constant of a given cell is 0.47 cm . The resistance of a solution placed in this
-1
cell is measured to be 31.6 ohm. The conductivity of the solution (in S cm-1 where S has usual
meaning) is :
(A) 0.15 (B) 1.5 (C) 0.015 (D) 150
Q.11 If 0.01 M solution of an electrolyte has a resistance of 40 ohms in a cell having a cell constant
of 0.4 cm-1 then its molar conductance in ohm-1 cm2 mol-1 will be :
(A) 104 (B) 103 (C) 102 (D) 10
Q.12 Which of the following solutions of KCl has the lowest value of specific conductance ?
(A) 1M (B) 0.1 M (C) 0.01 M (D) 0.001 M
Q.13 Which of the following solutions of KCl has lowest value of equivalent conductance ?
(A) 1M (B) 0.1M (C) 0.01 M (D) 0.001 M
44 ELECTROCHEMISTRY
Q.14 Under which of the following conditions, conductance, sp conductance and eq. conductance
are all equal ?
(A) 1000 cc of solution contains 1 eq. of electrolyte
(B) 100 cc of solution contains 1 eq. of electrolyte
(C) 10 cc of solution contains 1 eq. of electrolyte
(D) 1 cc of solution contains 1 eq. of electrolyte
Q.15 If V , in the equation = sp. cond× V, is the volume in cc containing 1 eq. of the electrolyte ;
V for a N/10 solution will be :
(A) 10 cc (B) 100 cc (C) 1000 cc (D) 10,000 cc
Q.16 At infinite dilution , the eq. conductances of CH3COONa , HCl and CH3COOH are 91 ,
426 and 391 mho cm2 respectively at 25 ºC. The eq. conductance of NaCl at infinite dilution
will be :
(A) 126 (B) 209 (C) 391 (D) 908
Q.17 CH3COOH = 20 ohm cm eq and CH3COOH = 400 ohm cm equiv-1 , then pH of 1 M
-1 2 -1 -1 2
CH3COOH solution is :
(A) 1.3 (B) 0 (C) 1.7 (D) 4
Q.18 The equivalent conductivity of 0.1 M weak acid is 100 times less than that at infinite
dilution. The degree of dissociation is :
(A) 100 (B) 10 (C) 0.01 (D) 0.001
Q.19 Molar ionic conductivities of a bivalent electrolyte are 57 and 73. The molar conductivity of
the solution will be :
(A) 130 S cm2 mol-1 (B) 65 S cm2 mol-1 (C) 260 S cm2 mol-1 (D) 187 S cm2 mol-1
Q.20 The conductivity of the saturated solution of some bivalent salt XY is 3.06 × 10-6 ohm-1 cm-1
and its equivalent conductivity is 1.53 ohm-1 cm2 equi-1. The value of Ksp of XY is :
(A) 4 × 10–6 (B) 2.5 × 10-9 (C) 2.5 × 10-13 (D) 1 × 10-6
Q.21 The conductivity of 0.25 M solution of univalent weak electrolyte XY is 0.0125 -1 cm-1. The
value of m of XY is 500 -1 cm2 mol-1. the value of Ostwald dilution constant of AB is :
(A) 2.5 × 10-3 (B) 2.5 × 10-4 (C) 2.8 × 10-3 (D) 2.8 × 10-4
Q.22 Equivalent conductance at infinite dilution of BaCl2, H2SO4 and HCl aq. solutions are x1, x2
and x3 respectively. Equivalent conductance of BaSO4 solution is :
(A) x1 + x2 - x3 (B) x1 - x2 - x3 (C) x1 + x2 - 2x3 (D) x1 - 2x2 + x3
Q.23 CH3COOH is titrated with NaOH solution. Which is true statement ?
(A) conductance decreases upto equivalence point, after which it increases
(B) conductance increases upto equivalence point, after which it decreases
(C) conductance first increases (but not rapidly) upto equivalence point and then increases
rapidly after equivalence point
(D) none of these
Q.24 If molar conductance at infinite dilution of (NH4)2SO4, NaOH and Na2SO4 solutions are x1, x2
and x3 respectively, then molar conductance of NH4OH solution is -
x1 2 x 2 x 3 x1 x 2 x 3
(A) (B) x1 2x 2 x 3 (C) (D) x1 x 2 x 3
2 2
Q.25 If NaOH with HCl , variation of conductance y-axis with addition of HCl (x-axis) will be :
(A) (B) (C) (D)
