What is the unit of molar conductivity, denoted by ${\Lambda }_m$?

Solution

1. Molar conductivity is defined as ${\Lambda }_m=\frac{\kappa }{C}$.
2. The unit of conductivity $\kappa$ is ${\text{S cm}}^{-1}$.
3. The unit of concentration $C$ is ${\text{mol cm}}^{-3}$.
4. Dividing these gives $\frac{{\text{S cm}}^{-1}}{{\text{mol cm}}^{-3}}={\text{S cm}}^2{\text{mol}}^{-1}$.
5. Hence the answer is (A).