Question

A possible mechanism for the gas phase reaction of NO and H2 is as follows: Step 1 2NO N2O2 Step 2 N2O2 + H2 N2O + H2O Step 3 N2O + H2 N2 + H2O Which of the following statements concerning this mechanism is not directly supported by the information provided? a. N2O2 is an intermediate. b. All steps are bimolecular reactions. c. The rate expression for step 1 is rate = k[NO]2. d. Step 1 is the rate determining step. e. There is no catalyst in this reaction. 1 points Question 9

Answer 1

Answer: Option (d) is the correct answer.

Explanation:

Steps involved for the given reaction will be as follows.

Step 1: $2NO \Leftrightarrow N_{2}O_{2}$    (fast)

Rate expression for step 1 is as follows.

               Rate = k $[NO]^{2}$

Step 2: $N_{2}O_{2} + H_{2} \rightarrow N_{2}O + H_{2}O$

This step 2 is a slow step. Hence, it is a rate determining step.

Step 3. $N_{2}O + H_{2} \rightarrow N_{2} + H_{2}O$    (fast)

Here, $N_{2}O_{2}$ is intermediate in nature.

All the steps are bimolecular and it is a second order reaction. Also, there is no catalyst present in this reaction.

Thus, we can conclude that the statement step 1 is the rate determining step, concerning this mechanism is not directly supported by the information provided.