Question

The conductivity of a weak mono-basic acid in 0.2 N solution at ${20}^{o}C$ is $0.0023Sc{m}^{-1}$ and the equivalent conductivity at infinite dilution is $160.2Sc{m}^{2}e{q}^{-1}$. Dissociation constant of weak acid is $X\times {10}^{-3}$, Value of $X$ is:

Answer 1

As we know,

${\Lambda }_{eq}=\frac{1000\times k}{C}=\frac{1000\times 0.0023}{0.2}=11.5$

$\alpha =\frac{{\Lambda }_{eq}}{{\Lambda }^0}=\frac{11.5}{160.2}=0.071$

and eqm constant

$K=c{\alpha }^2=0.2\times (0.071{)}^2=0.001=1\times {10}^{-3}$

[Note: Molarity = Normality : since monobasic acid]