Question

Resistance of Conductivity cell when filled with a solution of electrolyte of concentrated $0.1$M is $100$ ohms and conductivity of this solution is $1.2s{m}^{-1}$ when some cell is filled with $0.2$M of the same solution; resistance of solution is $500$ ohm. Calculate molar conductivity of $0.2$M solution.

Answer 1

We know, $K=K\times G$

$K=K\times \frac{1}{R}(\because G=\frac{1}{R})$

$\therefore K_1{R}_1=K_2{R}_2$ as cell constant is same.

$1.2\times 100=K_2\times 500$

$K_2=0.24{sm}^{-1}$

we know, ${\Lambda }_m=\frac{K}{C}$

${\Lambda }_m=\frac{0.24{sm}^{-1}}{0.2mol/{dm}^3}$

${\Lambda }_m=\frac{0.24s{cm}^{-1}\times 10}{0.2mol/{cm}^3}$

${\Lambda }_m=125{cm}^2{mol}^{-1}$