Question

The ionization constant of a weak electrolyte is $25\times {10}^{-6}$ while the equivalent conductance of its $0.01M$ solution is $19.6Sc{m}^{2}e{q}^{-1}$. The equivalent conductance of the electrolyte at infinite dilution (in $Sc{m}^{2}e{q}^{-1}$) will be

• A. $250$
• B. $196$
• C. $392$
• D. $384$

Answer 1

The correct option is C $392$

$K_a=25\times {10}^{-6}{\wedge }_{eq}=19.6Sc{m}^{2}e{q}^{-1}C=0.01M{K}_a=0.01\times {\alpha }^2$
(Assume $\alpha$ is very very less than 1)
$\Rightarrow \alpha =\sqrt{\frac{25\times {10}^{-6}}{{10}^{-2}}}=5\times {10}^{-2}\alpha =5\times {10}^{-2}=\frac{{\Lambda }_{eq}}{{\Lambda }_{eq}^{\infty }}=\frac{19.6}{{\Lambda }_{eq}^{\infty }}\Rightarrow {\Lambda }_{eq}^{\infty }=\frac{19.6}{5\times {10}^{-2}}=392Sc{m}^{2}e{q}^{-1}$