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Question:

Molar conductivity (Λm) of an aqueous solution of sodium stearate, which behaves as a strong electrolyte, is recorded at varying concentrations (c) of sodium stearate. Which one of the following plots provide the correct representation of micelle formation in the solution?

Solution:

Correct option is A. As the concentration of sodium stearate increases beyond CMC, stearate ions get clubbed together and form micelles. This abruptly causes the concentration of the current carrier anions to decrease. This is reflected by the sharp change in Λm at CMC, followed by a greater rate of decrease of Λm with C.