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 $392$

$K_a=C{\alpha }^2$

$\alpha =\sqrt{\frac{K_a}{C}}$

$\alpha =\sqrt{\frac{25\times {10}^{-6}}{{10}^{-2}}}=5\times {10}^{-2}$

${\wedge }_{eq}^{\infty }=\frac{{\wedge }_{eq}}{\alpha }=\frac{19.6}{5\times {10}^{-2}}=392$

Hence, the correct option is $\text{C}$