Question

${\text{A 5.0 m mol dm}}^{-3}$ aqueous soluion of $KCI$ has a conductance of $0.55mS$ when when measued in a cell of cell constant $1.3c{m}^{-1}$. The molar conductivity of this solution in $mS{m}^2$ ${\text{mol}}^{-1}$ is

(Round off to the Nearest Integer)

• A. 14
• B. 14.00
• C. 14.0

Answer 1

Answer: (A), (B), (C)

$\text{Conductance}=\frac{\text{Conductivity}}{\text{Cell Constant}}$

$\therefore \text{Conductivity}=0.55\times {10}^{-3}\times 1.3Sc{m}^{-1}$



$\text{Molar conductivity}=\frac{\text{Conductivity}\left(Sc{m}^{-1}\right)\times 1000}{\text{Molarity}\left(\text{mol/L}\right)}$

$\text{Molar conductivity}=\frac{0.55\times {10}^{-3}\times 1.3\times 100}{5\times {10}^{-3}}$

$\text{Molar conductivity}=143Sc{m}^2{\text{mol}}^{-1}$

$\text{Molar conductivity}=14.3mS{m}^2{\text{mol}}^{-1}$

$\text{Molar conductivity}\approx 14mS{m}^2{\text{mol}}^{-1}$