Question

The equivalent conductance of $\frac{M}{32}$ solution of a weak monobasic acid is $8mhoc{m}^2$ and at infinite dilution is $400mhoc{m}^2$. The dissociation constant of this acid is

• A. $1.25\times {10}^{-6}$
• B. $6.25\times {10}^{-4}$
• C. $1.25\times {10}^{-4}$
• D. $1.25\times {10}^{-5}$

Answer 1

The correct option is D $1.25\times {10}^{-5}$

$\alpha =\frac{\Lambda }{{\Lambda }_{\infty }}=\frac{8}{100}=2\times {10}^{-2}$
Dissociation constant $K={\alpha }^{2}C$
$K=(2\times {10}^{-2}{)}^2\times \frac{1}{32}=1.25\times {10}^{-5}$