Question

The rate law for a reaction between the substances A and B is given by, rate = k[A]ⁿ [B]^m. On halving the concentration of A and doubling the concentration of B, the ratio of the new rate to the earlier rate of the reaction will be as ____________.

Options

• `1/(2^(("m"+"n")))`

• (m + n)

• (n − m)

• 2^(m−n)

Answer 1

The rate law for a reaction between the substances A and B is given by, rate = k[A]ⁿ [B]^m. On halving the concentration of A and doubling the concentration of B, the ratio of the new rate to the earlier rate of the reaction will be as 2^(m−n).

Explanation:

rate = k[A]ⁿ [B]^m

`("rate")_2/("rate")_1 = ("k" [1//2"A"]^"n" [2"B"]^"m")/("k" ["A"]^"n" ["B"]^"m")`

= `2^"m" xx (1/2)^"n"`

= 2^(m−n)