The following curve is obtained when molar conductivity λm (y-axis) is plotted against the square root of concentration C1/2 (x-axis) for two electrolytes A and B.
(a) What can you about the nature of the two electrolytes A and B.
(b) How do you account for the increase in molar conductivity λm for the electrolytes A and B on dilution.
(a) A is strong electrolyte and B is weak electrolyte.
(b) The molar conductivity of a strong electrolyte:
(A) increase slightly as the concentration increased. This is because greater inter ionic attractions retrad the motion of the ions therefore molar conductivity decreases.The molar conductivity of a weak electrolyte.
(B) increase with decrease in the concentration of the solute in solution. The increase is very rapid at lower concentrations. The increase in the molar conductance with dilution is due to an increase in the effective degree of ionisation (α) at lower concentration and release of more full ions in the solution.
= 1.05 V – 0.0295 x log 80
= 1.05 V – 0.0295 x 1.9031
= 1.05 V – 0.056 = 0.99 V.