Question

A $5.0mmold{m}^{-3}$ aqueous solution of $KCl$ has a conductance of $0.55mS$ when measured in a cell constant $1.3c{m}^{-1}$. The molar conductivity of this solution is________ $mS{m}^{2}mo{l}^{-1}$ (Round off to the Nearest Integer)

Answer 1

Answer: 14

Given conc ${}^n$ of $KCl=\frac{m\cdot mol}{L}$

Conductance $(G)=0.55mS$

Cell constant $\left(\frac{\ell }{A}\right)=1.3c{m}^{-1}$

To Calculate : Molar conductivity

$\left({\lambda }_m\right)$ of sol. $\to$ Since ${\lambda }_m=\frac{1}{1000}\times \frac{k}{m}$

$\to$ Molarity $=5\times 10^{-3}\frac{mol}{L}$

$\to$ Conductivity $=G\times \left(\frac{\ell }{A}\right)=0.55mS\times \frac{1.3}{\frac{1}{100}}{m}^{-1}$

$=55\times 1.3mS{m}^{-1}$

$e{q}^n(1){\lambda }_m=\frac{1}{1000}\times \frac{55\times 1.3}{\left(\frac{5}{1000}\right)}\frac{mS{m}^2}{mol}$

$\Rightarrow {\lambda }_m=14.3\frac{mS{m}^2}{mol}$