Question

The equivalent conductance a $\frac{M}{32}$ solution of a weak monobasic acid is $8.0$ $mhoc{m}^2$ and at infinite dilution is $400mhoc{m}^2\hat{A}$. What is the dissociation constant of this acid?

Answer 1

Degree of dissociation $=\alpha =\frac{equivalentConductanceofM/32Solution}{equivalentConductanceatinfinitedilution}$

$\therefore \alpha =2\times {10}^{-2}$

$HA⟶H^{+}+A^{-}$

$1-\alpha$ $\alpha$ $\alpha$

$K_{\alpha }=\frac{{\alpha }^2}{1-\alpha }=\frac{4\times {10}^{-4}}{1-0.02}=4.08\times {10}^{-4}$