Question

The equivalent conductance of $M / 32$ solution of a weak monobasic acid is $8.0\, mho\, cm ^{2}$ and at infinite dilution is $400\, mh \circ cm ^{2}$. 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

Answer: (D)

$\alpha=\frac{\wedge e q}{\wedge_{e q}^{0}}=\frac{8}{400} $
$\Rightarrow 2 \times 10^{-2}$
$k=c \alpha^{2}=\frac{1}{32} \times\left(2 \times 10^{-2}\right)^{2}$
$=\frac{4}{32} \times 10^{-4}=1.25 \times 10^{-5}$