Question

Molar conductivities at infinite dilution of $KCl,HCl$ and $C{H}_{3}COOK$ are $0.013,0.038$ and $0.009S{m}^{2}mo{l}^{-1}$ respectively at $291K$. If the conductivity of $0.001MC{H}_{3}COOH$ is $2.72\times {10}^{-3}S{m}^{-1}$. Find the degree of ionization of $C{H}_{3}COOH.$

Answer 1

${\Lambda }^0\left(C{H}_{3}COOH\right)={\Lambda }^0\left(C{H}_{3}COOK\right)+{\Lambda }^0\left(HCl\right)-{\Lambda }^0\left(KCl\right)$

$=0.009+0.038-0.013=0.034S{m}^{2}mo{l}^{-1}$

Also, $\Lambda =\frac{\kappa }{C}=\frac{2.72\times {10}^{-3}\times {10}^{-3}}{0.001}=2.72\times {10}^{-3}S{m}^2/mol$.

The degree of the dissociation is given by the expression $\alpha =\frac{\Lambda }{{\Lambda }^0}=\frac{2.72\times {10}^{-3}}{0.034}=0.08$