NEET 2021 Chemistry Question 70 Solution

Kohlrausch's law states that the limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of the anion and cation of the electrolyte: $$\Lambda_m^\circ = \nu_+ \lambda_+^\circ + \nu_- \lambda_-^\circ$$

To calculate $\Lambda_m^\circ(CH_3COOH)$, we combine the limiting molar conductivities of the three strong electrolytes ($CH_3COONa$, $HCl$, and $NaCl$): $$\Lambda_m^\circ(CH_3COOH) = \lambda^\circ(CH_3COO^-) + \lambda^\circ(H^+)$$ Expressing in terms of the given salts:

Substitute the given numerical values: - $\Lambda_m^\circ(CH_3COONa) = 91.0\text{ S cm}^2\text{ mol}^{-1}$ - $\Lambda_m^\circ(HCl) = 426.16\text{ S cm}^2\text{ mol}^{-1}$ - $\Lambda_m^\circ(NaCl) = 126.45\text{ S cm}^2\text{ mol}^{-1}$