Question

pH of 0.1 M $C{H}_{3}COOH$ solution is 3 at $25{}^{o}C.$ If limiting molar conductivity of $C{H}_{3}CO{O}^{-}$ and $H^{+}$ are 40 and $350Sc{m}^{2}mo{l}^{-1}$. The molar conductance (in $Sc{m}^{2}mo{l}^{-1}$) at $25{}^{o}C$ for 0.1 M $C{H}_{3}COOH$ is:

• A. 0.039
• B. 3.9
• C. 92
• D. 340

Answer 1

The correct option is A 0.039

Given data,

$pH=3,H^{+}={10}^{-3}$

${\lambda }_m\left(C{H}_{3}CO{O}^{-}\right)=40,{\lambda }_m\left(H^{+}\right)=350$

$C{H}_{3}COOH=0.1M$

${\wedge }_m={\lambda }_m\left(C{H}_{3}CO{O}^{-}\right)+{\lambda }_m\left(H^{+}\right)$

$=40+350$

${\wedge }_m=390$

${\wedge }_m=\frac{k\times 1000}{C}=\frac{k\times 1000}{0.1}$

$K=\frac{{\wedge }_m\times 0.1}{1000}=\frac{390\times 0.1}{1000}$

$K=0.039Sc{m}^{2}mo{l}^{-1}$