Define Rate law and Rate constant.

Explanation

(i) Rate law : The expression in which reaction rate is given in terms of molar concentration of the reactants with each term raised to some power, which may not be same as the Stoichiometric coefficient of the reacting species in a balanced chemical equation.
`xA +yB rarr "products"`
`"Rate=k[A]^(m)[B]^(n)`
`k="Rate constant"`
(ii) Rate constant : For a involving the reactants A and B,
Reaction rate `=k[A]^(m)[B]^((n)`
The constant k is called rate constant of the reaction.
If `[A]=1M and [B]=1M`, Reaction rate = k
Thus, the rate constant (k) of a reaction is equal to the rate of reaction when the concentration of each reactant is equal to `"1 mol L"^(-1)`
The change in the concentration of reactant or product per unit time under the condition of unit concentration of all the reactant.