Using the information in the table, the rate law for the reaction A(g) + 3 B(g) → C(g) + 2 D(g) is

Question

Using the information in the table, the rate law for the reaction A(g) + 3 B(g) → C(g) + 2 D(g) is

Table

[A0] (M) [B0] (M) Rate (M/min)

0.300 0.180 0.0234

0.300 0.360 0.0934

0.150 0.180 0.0234

options

a) Rate K[A][B]^3

b) Rate k[B]^2

c) Rate k[A]^2[B]

d) Rate k[A][B]^2

Answer 1

Compare row 1 to row 2: [A] remains constant while [B] doubles. The rate increases 4x. This means the reaction is 2nd order in B

Compare row 3 to row 1: [B] remains constant while [A] doubles. The rate doesn't change. This means the reaction is zero order in A (i.e. the concentration of A has no effect on the rate)

Thus, we can write the rate law as

Rate = k[B]² (option b is correct)