The reaction of NO gas with H₂ gas has the following rate law: Rate = k[H₂][NO]². A proposed mechanism is:
Step 1:
Step 2:
What is the molecularity of steps 1 and 2, and which step is the slow, or rate-determining, step?

Question

The reaction of NO gas with H₂ gas has the following rate law: Rate = k[H₂][NO]². A proposed mechanism is:
Step 1: The reaction of NO gas with H2 gas has the following rate law: Rate = k[H2][NO]2. A proposed mechanism is: Step 1: Step 2: What is the molecularity of steps 1 and 2, and which step is the slow, or rate-determining, step? A) 2; 2; step 1 B) 4; 4; step 2 C) 3; 2; step 1 D) 3; 2; step 2 E) Cannot be determined from the information provided.

Step 2:

What is the molecularity of steps 1 and 2, and which step is the slow, or rate-determining, step?

Quizplus · Accepted Answer

The molecularity of step 1 is 3 (one NO molecule and two H₂ molecules collide to form the intermediate). The molecularity of step 2 is 2 (one intermediate and one NO molecule collide to form the product). The slow, or rate-determining, step is the one with the highest activation energy, which is usually the step with the highest molecularity. In this case, it is step 1 (which has a molecularity of 3), because it involves the collision of three molecules. Therefore, the answer is C) 3; 2; step 1.

The Reaction of NO Gas with H2 Gas Has the Following

The Reaction of NO Gas with H₂ Gas Has the Following