Question

What is the overall order of the following reaction, given the rate law? X + 2Y = 42 Rate = K[X][Y] 1st 3rd 5th 2 nd Next → F5 F6 F FBI

Answer 1

Let us consider a reaction

mA + nB ---------> Products

According to Law of mass action, at a given temperature rate of any reaction is directly proportional to the product of the concentrations of reactants which are raised to their stoichiometric coefficients.

Or

The rate of a reaction at a given temperature is directly proportional to the product of the active masses of the reactants.

Rate ∝ [A]m[B]n

Rate = K [A]m[B]n ------->(1)

Where K is the rate constant

The above relation is called rate equation or rate law or rate expression.

Order of a reaction is the sum of the powers of the concentration terms in rate equation or rate law.

In equation (1), sum of the powers of concentrations terms is m (power of reactant A) + n (power of reactant B)

Overall order of the reaction = m+n

Given rate equation is

Rate = K[X][Y]

Order w.r.t reactant X is 1

Order w.r.t reactant Y is 1.

Sum of powers of concentration terms is 1+1 = 2.

Overall order of the reaction is 2.

Option 4 is the correct one. (Last option).