NTA Abhyas NEET2020ChemistryChemical KineticsPractice
Consider the reaction 2 N O 2 ( g ) + O 3 ( g ) → N 2 O 5 ( g ) + O 2 ( g ) The reaction of nitrogen dioxide and ozone represents is first order in N O 2 ( g ) and in O 3 ( g ) . Which of these possible reaction mechanism is consistent with the rate law? Mechanism I: NO 2 (g) + O 3 (g) → NO 3 (g) + O 2 (g) (slow) NO 3 (g) + NO 2 (g) → N 2 O 5 (g) (fast) Mechanism II: O 3 (g) → O 2 (g) + [O] (fast) NO 2 (g) + [O] → NO
Options
- AOnly I
- BOnly II
- CBoth I and II
- DNeither I nor II
Correct answer
C. Both I and II
Step-by-step solution
Mechanism I: R a t e = k [ N O 2 ] [ O 3 ] Slow step is rate determining Mechanism II: Rate = k ′ [ N O 2 ] [ O ] …(i) From 1st step K = [ O 2 ] [ O ] [ O 3 ] (k = eq. constant) [O] = k O 3 O 2 ...(ii) From equation (i) & (ii) Rate = k ′ [ N O 2 ] [ O 3 ] [ O 2 ] − 1 So both mechanism show that reaction is first order with respect to N O 2 and O 3 .