The unit of rate constant of second order reaction is

Explanation

The rate of a reaction has units of mol dm-3 sec-1. For a second-order reaction, where rate = k[reactant]2, the units of the rate constant (k) can be found by dividing the rate units by the concentration units squared. The concentration of reactants is in mol dm-3, so the square of concentration is mol2 dm-6. Therefore, the units of the rate constant k are:k = (mol dm-3 sec-1) / (mol2 dm-6) = mol-1 dm3 sec-1.Option A represents the units of the rate itself, not the rate constant. Option B is not a valid unit for any standard reaction order. Option C is the unit for a first-order reaction rate constant. Hence, the correct answer is Option D.