Unit of rate constant for second-order reaction is

Correct option is C

The unit of the rate constant for a second-order reaction is mol⁻¹ L S⁻¹. This can be derived from the general rate law of a second-order reaction, where the rate is proportional to the square of the concentration of the reactant, and hence the unit for the rate constant is mol⁻¹ L S⁻¹.