The rate expression for a first order reaction could be

A.) Rate=k[A]

B.) Rate=k[A]^2[B]

C.) Rate=k[A][B]

D.) Rate=k[A]^2[B]^2

A.) Rate=k[A]

Explanation:

The rate law has the following general form:

Rate = k. [A]ᵃ. [B]ᵇ

where,

k is the rate constant

[A] and [B] are the molar concentrations of the reactants

a and b are the reaction orders with respect to A and B

a + b is the overall order of reaction

The rate expression for a first order reaction could be

A.) Rate=k[A] YES. The reaction order is 1.

B.) Rate=k[A]²[B] NO. The reaction order is 2 + 1 = 3.

C.) Rate=k[A][B] NO. The reaction order is 1 + 1 = 2.

D.) Rate=k[A]²[B]² NO. The reaction order is 2 + 2 = 4