Which among the following statements is true for conductivity?
Which among the following statements is true for conductivity?
It is inversely proportional to resistivity.
It is inversely proportional to molar conductivity.
It is directly proportional to resistivity.
It is directly proportional to resistance.
Solution
Specific conductance/ Conductivity (k): -
It is defined as the reciprocal of specific resistance, or resistivity, $\mathrm{k}=\frac{1}{\rho}$
$\begin{aligned}
& \mathrm{R}=\rho \frac{\ell}{\mathrm{A}} \\
& \frac{1}{\rho}=\frac{1}{\mathrm{R}} \cdot \frac{\ell}{\mathrm{A}} \\
& \mathrm{k}=\mathrm{G} \times \mathrm{G}^*
\end{aligned}$
Specific conductance $=$ Conductance $\times$ Cell constant
Hence specific conductivity of a solution is defined as the conductance offered by $1 \mathrm{~cm}^3$ of electrolytic solution.
Unit of $\mathrm{k}$ is ohm ${ }^{-1} \mathrm{~cm}^{-1}$