What do you understand by the rate law and rate constant of a reaction? Identify the order of a reaction if the units of its rate constant are:

(i) L^-1mol s^-1

(ii) L mol^-1 s^-1

Rate law is an expression which shows how the rate depends on the concentration of reactants. Rate of a reaction depends on-

(i) Concentration of reactants.

(ii) Temperature at which reaction occurs.

(iii) Presence of catalyst.

(iv) Surface area of solid reactants.

If a reaction is of second order in A and first order in B, the differential rate equation is-

Rate = = k[A][B]²

Where k is the rate constant.

If the reaction is zero order, the rate constant has exactly the same units as the rate of the reaction mol L^-1 s ^-1.

If the reaction is second order, then two units of concentration are already present so the rate constant needs reciprocal time plus inverse units of concentration, L mol^-1 s^-1.