Chemistry class 12th Molar conductivity numericals

Molar Conductivity: 15 Numericals with Solutions


1. Calculate the molar conductivity (Lambda_m) of a 0.01 M NaCl solution if its conductivity
(k) is 1.2 x 10-² S/m.

Solution:
Lambda_m = (k x 1000) / C
= (1.2 x 10-² x 1000) / 0.01
= 1200 S·m²/mol


2. The molar conductivity of KCl at infinite dilution (Lambda_m0) is 149.86 S·m²/mol. If
Lambda_m at 0.1 M is 85.3 S·m²/mol, calculate the degree of dissociation.

Solution:
alpha = Lambda_m / Lambda_m0
= 85..86
= 0.569 or 56.9%


3. Calculate the conductivity (k) of a 0.05 M NaOH solution if its molar conductivity
(Lambda_m) is 240 S·m²/mol.

Solution:
k = (Lambda_m x C) / 1000
= (240 x 0.05) / 1000
= 0.012 S/m


4. The limiting molar conductivities of Na+ and Cl- are 50.1 and 76.3 S·m²/mol respectively.
Calculate the limiting molar conductivity of NaCl.

Solution:
Lambda_m0(NaCl) = Lambda_m0(Na+) + Lambda_m0(Cl-)
= 50.1 + 76.3
= 126.4 S·m²/mol


5. If the conductivity of 0.2 M CH3COOH is 4 x 10-³ S/m and its limiting molar conductivity is
390 S·m²/mol, calculate its degree of ionization.

Solution: