Question

The equivalent conductances of two strong electrolytes at infinite dilution in H2O (where ions move freely through a solution) at 25°C are given below :

$\Lambda_{CH_{3}COONa}^{0} = 91.0$Scm2/equiv and$\Lambda_{HCl}^{0} = 426.2$

Scm2/equiv

What additional information/quantity one needs to calculate $\Lambda$ŗ of an aqueous solution of acetic acid

• A. The limiting equivalent conductance of H+
• B. $\Lambda^{0}$of chloroacetic acid (ClCH2COOH)
• C. $\Lambda^{0}$of NaCl
• D. $\Lambda^{0}$of CH3COOK

Answer 1

Answer: (C)

$\Lambda^{0}$of NaCl

Answer 2

According to Kohlrausch's law the molar conductivity at infinite diluation$\left( \Lambda^{0} \right)$ for weak electrolyte CH3COOH is $\Lambda_{\text{CH3COOH}}^{0}\text{ =}\Lambda_{\text{CH3COONa}}^{0}\text{ + }\Lambda_{\text{HCI}}^{0}\text{ - }\Lambda_{\text{NaCI}}^{0}\$So for

calculating the value of $\Lambda_{CH3COOH}^{0}$, value of $\Lambda_{\text{NaCI}}^{0}$ should

also be known.