Question
Question: Consider this reaction : 2 NO<sub>2</sub> (g) + O<sub>3</sub> (g) ¾® N<sub>2</sub>O<sub>5</sub> (g)...
Consider this reaction :
2 NO2 (g) + O3 (g) ¾® N2O5 (g) + O2 (g)
The reaction of NO2 (g) and O3 (g) represented is first order in NO2 (g) and in O3 (g) Which of the following mechanism is/are consistent with the rate law ?
MechanismI : NO2 (g) + O3 (g) ¾® NO3 (g) + O2 (g) (slow)
NO3 (g) + NO2 (g) ¾® N2O5 (g) (fast)
MechanismII : O3 (g) ⟶O2 (g) + O (fast)
NO2 (g) + O ¾® NO3 (g) (slow)
NO3 (g) + NO2 (g) ¾® N2O5 (g) (fast)
A
I only
B
II only
C
Both I & II
D
Neither I nor II
Answer
I only
Explanation
Solution
As per mechanism (I), rate = k [NO2] [O2]
slowest step is the r.d.s.
As per mechanism (II), rate = k [NO2] [O]
Keq = [O3][O2][O]
or [O] = Keq [O2][O3]
\ as per mechanism (II), rate = k Keq [NO2] [O3] [O2]–1