JEE Main & Advanced Sample Paper JEE Main - Mock Test - 1

If \[0.01\text{ }M\]solution of an electrolyte has a resistance of 40 ohms in a cell having a cell constant of \[0.4\,c{{m}^{-1}},\] then its molar conductance in \[oh{{m}^{-1}}\,\,c{{m}^{2}}\,\,mo{{l}^{-1}}\].

A) \[{{10}^{2}}\]

B) \[{{10}^{4}}\]

C) 10

D) \[{{10}^{3}}\]

Correct Answer: D

Solution :

Molarity\[=0.01M;\]Resistance \[=40\,ohm;\]

Cell constant \[\left( \frac{l}{A} \right)=0.4c{{m}^{-1}}\]

Specific conductivity \[(k)=\frac{cell\,\,\text{constant}}{\text{resistance}}\]\[=\frac{0.4}{40}=0.01\,oh{{m}^{-1}}c{{m}^{-1}}\]

Molar conductance \[({{\wedge }_{m}})=\frac{1000k}{Molarity}\]\[=\frac{1000\times 0.01}{.01}={{10}^{3}}oh{{m}^{-1}}c{{m}^{2}}mo{{l}^{-1}}\]