Answer:
Step 1 H2 + 2 NO β N2O + H2O (slow)
step 2 N2O + H2 β N2 + H2O (fast)
Explanation:
It is known that the slowest step in a reaction is the rate determining step in a sequence of reactions (reaction mechanism).
We have two important pieces of information in the question to guide our decision making process.
The overall reaction equation, and the rate expression. The two;
2 H2 + 2 NO β N2 + 2 H2O and rate = k[H2][NO]2 all support the answer given above.