Question

The molar conductivity of a weak electrolyte when plotted against the square root of its concentration, which of the following is expected to be observed?

• A. A small decrease in molar conductivity is observed at infinite dilution.
• B. A small increase in molar conductivity is observed at infinite dilution.
• C. Molar conductivity increases sharply with increase in concentration.
• D. Molar conductivity decreases sharply with increase in concentration.

Hint:

At infinite dilution, weak electrolytes have a limiting molar conductivity, and further dilution does not increase their conductivity significantly.

Answer 1

The Correct Option is A

For a weak electrolyte, the molar conductivity at infinite dilution decreases slightly with concentration. This is due to the decrease in the ionization of the electrolyte as its concentration increases, and hence the ion conductivity is reduced. Thus, the correct observation is that the molar conductivity decreases with increasing concentration until it reaches a limiting value at infinite dilution.