NEET Chemistry NEET PYQ-Electrochemistry

The specific conductance of a 0.1 N KCl solution at \[23{}^\circ C\] is \[0.012\,\,oh{{m}^{-1}}c{{m}^{-1}}\]. The resistance of cell containing the solution at the same temperature was found to be 55 ohm. The cell constant will be: [AIPMT 1999]

A) \[0.142\text{ }c{{m}^{-1}}\]

B) \[0.66\text{ }c{{m}^{-1}}\]

C) \[0.918\text{ }c{{m}^{-1}}\]

D) \[1.12\text{ }c{{m}^{-1}}\]

Correct Answer: B

Solution :

[b] \[{{K}_{s}}\] (sp. conductivity) \[=\frac{1}{R}\times \frac{l}{a}\]

\[\frac{l}{a}=\] cell constant of cell

So, \[0.012\,oh{{m}^{-1}}\,c{{m}^{-1}}=\frac{1}{55\,ohm}\times \frac{l}{a}\]

\[\frac{l}{a}\] (cell constant) \[=55\times 0.012=0.66\,c{{m}^{-1}}\]