Answer:
Option A
Explanation:
Key Idea Kohlraush law of independent migration of ions can be used to calculate $\wedge_{m}^{o}$ for weak electrolyte such as acetic acid
Given, $\wedge_{m(NaAC)}^{o}= 91 $ $S cm^{2}mol^{-1}$
$\wedge_{m(HCl)}^{o}$= 425.9 S $cm^{2}mol^{-1}$
$\wedge_{m(NaCl)}^{o}= 126.4 $ S $cm^{2}mol^{-1}$
Using Kohlrausch law, to find the molar conductivity of acetic acid
$\wedge_{m(HAc)}^{o}= \lambda_{H^{+}}^{o}+\lambda_{AC^{-}}^{o}$
=$ \lambda_{H^{+}}^{o}+\lambda_{Cl^{-}}^{o}+\lambda_{AC^{-}}^{o}+\lambda_{Na^{+}}^{o}-\lambda_{Cl^{-}}^{o}-\lambda_{Na^{+}}^{o}$
=$ \wedge_{m(HCl)}^{o}+\wedge_{m(NaAC)}^{o}-\wedge_{m(NaCl)}^{o}$
( 425.9+91.0-126.4) S cm2 mol-1
= 390.5 S cm2 mol-1
