QJEEM06Ch80b8: JEE Main 2006 Chemistry - Class 12 JEEM06Ch80b8 Solution: The following mechanism has been proposed for the reaction of…

Question

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The following mechanism has been proposed for the reaction of NO with Br₂ to form NOBr:
NO(g) + Br₂ (g)

\leftrightharpoons

NOBr₂ (g)
NOBr₂ (g) + NO (g)

\to

2NOBr (g)
If the second step is the rate determining step, the order of the reaction with respect to NO(g) is

Accepted Answer

\left( i \right)\,\,\,\,\,\,\,\,\,NO\left( g \right) + B{r_2}\left( g \right)\,\,\,\rightleftharpoons\,NOB{r_2}\left( g \right)

(i i) N O B r_{2} (g) + N O (g) \overset{}{⟶} 2 N O B r (g)

Rate law equation

= k\left[ {NOB{r_2}} \right]\left[ {NO} \right]

But

NOB{r_2}

is intermediate and

must not appear in the rate law equation

from

1

st step

{K_C} = {{\left[ {NOB{r_2}} \right]} \over {\left[ {NO} \right]\left[ {B{r_2}} \right]}}

\therefore

\,\,\,\,\,\left[ {NOB{r_2}} \right] = {K_C}\left[ {NO} \right]\left[ {B{r_2}} \right]

\therefore

\,\,\,\,

Rate law equation

= k.{K_C}{\left[ {NO} \right]^2}\left[ {B{r_2}} \right]

hence order of reaction is

2

w.r.t.

NO.

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