The following mechanism has been proposed for the reaction of NO with `Br_(2)` to from NOBr.
`NO(g)+Br_(2)hArrNOBr_(2)(g)`
`NOBr_(2)(g)+NO(g)rarr2NOBr(g)`
If the second step is the rate determining step, the order of the reaction with respect to NO(g) is

Options

A. 3
B. 2
C. 1
D. 0

Answer

B

Explanation

Rate `= k[NOBr_(2)][NO]`
From step I, `K_(q)=([NOBr_(2)])/([NO][Br^(2)])`
`[NOBr_(2)]=K_(eq)[NO\][Br_(2)]`
Substituting in eqn (i)
Rate `= k K_(eq)[NO]^(2)xx[Br_(2)]=k'[NO]^(2)[Br_(2)]`
`:.` Order of reaction with respect to `NO(g)` is 2.