In the rate equation
Rate = K[A]x [B]y
The x and y represents the dependence of the rate of reaction to change in the concentration of Aand B.
The sum of these exponents (x + y) in the above equation gives the overallorder of a reaction.
The sum of powers of the concentration of the reactants in the rate law expression is called the order of that chemical reaction.
For example, if the rate expression of a particular reaction is
Rate = K[A]1/2 [B]3/2
Then the order of the reaction will be
The reaction is of second order.