The following mechanism has been proposed for the reaction of NO with Br2

The following mechanism has been proposed for the reaction of NO with Br2 to form NOBr.

NO(g) + Br2(g) ↔ NOBr2(g)

NOBr2(g) + NO(g) → 2NOBr(g)

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

  1. 0
  2. 1
  3. 2
  4. 3

Answer

NO(g) + Br2(g) → NOBr2(g)

NOBr2(g) + NO(g) → 2NOBr(g) [RDS]

Rate of the reaction (r) = K[NOBr2][NO]

Where [NOBr2] = Kc[NO][Br2]

r = K’[NO]2[Br2]

The order of the reaction with respect to NO(g) = 2

The correct option is C.