Question

Nitrogen dioxide can react with ozone to form dinitrogen pentoxide and oxygen: 2NO2(g) + O3(g) → N2O(g) + O2(g) a) Based on the above information, write the two-step mechanism for this reaction: b) Identify and write the rate law for this reaction: c) Which step above is the rate determining step and why?

Answer 1

A two-step mechanism fonet the reaction 2002 egg + + Opcg) + O2 cg) N2O5 og + N205 NO2 + NO 2 (g be Step 1 Step 2 Com given as following llo Nor cgst Os cg + O2(g) (slow) NOBcg) + N205 cg) (fast) (g) the rate law for the above mechanism comes out to be Mate = k. tron].[03] on the rate of reaction only elepanels slowest ste the reaction stept is the slowest step. So, the state reaction will only depend stepo. [k is the state constant. the of mo mechanism and of on

c. As we discussed above, step 1 is the rate-determining step of the above reaction mechanism as it is the slowest step of the two elementary steps and the reaction rate equation depends on both the concentrations of $NO_{2}$ and $O_{3}$ which is outlined in step 1.

Some salient features of the above mechanism is-

• The two elementary reaction, when combined gives the overall reaction.
• Step 1 is the slowest step, so the rate law will follow step 1 only!
• There is an intermediate in the reaction which is $NO_{3}$ . It is produced in step 1 and gets consumed in step 2.
• There are no catalyst involved in the reaction
• The rate law of the reaction is given by -
• The overall order of the reaction is 2 (first order with respect to each of the reactants).