Conductance MCQ Questions
for CSIR UGC NET & GATE
Electrochemistry
Topic wise Assignment-1
Q1. The strength of a solution is 6 kg/L, unit conversion to g/ml and kg/m3 will be
(a) 60, 600
(b) 6, 6000
(c) 600, 60
(d) 6000, 6
Q2. The specific conductance of a solution is 0.176 S cm-1. If cell constant is 0.255 cm-1, The conductance in 'S' of the solution should be:
(b) 0.690
(c) 0.045
(d) 0.431
Q3. The equivalent conductance at infinite dilution of a strong electrolyte Λoeq can be obtained from the plot of
(b) Λ vs (C)1/2
(c) Λ vs C2
(d) Λ vs 1/C
Q4. If the specific conductance of an electrolytic solution is 0.2 S cm-1 and cell constant is 0.25 cm-1, the conductance of solution should be:
(b) 1.0 S
(c) 0.8 S
(d) 2.0 S
Q5. A 0.05 M KOH solution has a resistance of 31.6 Ω in a conductivity cell of cell constant 0.316 cm-1 at 298K. Calculate the molar conductivity.
(a) 200 S m2 mol-1
(b) 200 S cm2 mol-1
(c) 20 S m2 mol-1
(d) 20 S cm2 mol-1
Q6. When a certain conductivity cell was filled with 0.02 M KCl solution which has a specific conductance of 0.2 S m-1 and resistance of 80 Ω at 298K. When this solution is replaced by 0.0025 M K2SO4, it has a resistance of 320 Ω. Calculate the
(i) Cell constant, (ii) Conductivity of K2SO4, (iii) Molar conductivity of K2SO4
(a) 16 m-1, 0.05 S m-1, 0.02 S m2 mol-1
(b) 16 cm-1, 0.05 S cm-1, 0.02 S cm2 mol-1
(c) 16 m-1, 0.05 S cm-1, 0.02 S m2 mol-1
(d) 16 cm-1, 0.05 S m-1, 0.02 S cm2 mol-1
Q7. The specific conductance of a 0.01 M solution of CH3COOH was found to be 0.016 S m-1 at 298 K. Calculate the degree of dissociation of acetic acid given that Λom = 0.04 S m2 mol-1
(a) 0.4
(b) 0.004
(c) 0.04
(d) 0.0004
Q8. The molar conductivity of a 0.05 M MgCl2 is 194.2 S cm2 mol-1 at 298 K. A cell with electrodes that are 1.50 cm2 in surface area and 0.5 cm apart is filled with the MgCl2 solution. How much current will flow when potential difference between two electrodes is 5.0 V.
(a) 0.25 A
(b) 0.015 A
(c) 0.15 mA
(d) 0.15 A
Q9. The conductivity of 0.1 M NaOH solution is 0.0221 S cm-1. When an equal volume of 0.1 M HCl is added, the conductivity decreases to 0.0056 S cm-1. Calculate Λm(NaCl)
(a) 112 S m2 mol-1
(b) 112 S cm2 mol-1
(c) 0.112 S cm2 mol-1
(d) None
Q10. The molar conductivity of a 0.01 M weak acid (HX) at 298 K, measured in a cell of cell constant 0.4 cm-1 is 64.4 S cm2 mol-1. The limiting molar conductivities at infinite dilution of H+ and X- are 350 and 410 S cm2 mol-1. The pKa of HX at 298 K is
(b) 4.9
(c) 5.7
(d) 6.1
Answer Key
Q1-b, Q2-b, Q3-b, Q4-c, Q5-b, Q6-a, Q7-c, Q8-d, Q9-b, Q10-a