[LHM]

For the reaction:
2 H₂(g) + 2 NO(g) N₂(g) + 2 H₂O(g)
This mechanism is proposed:
step 1: H₂ + NO H₂O + N
step 2: N + NO N₂ + O
step 3: O + H₂ H₂O

If we're given that the 2nd step is the rate law, then how come rate=k[H₂][NO]², instead of rate=k[H₂][NO]²/[H₂O]? Like why can just disregard the [H₂O], since it's a gas in the overall equation?

[samiam]

what?
You are saying step 2 is the rate law? so the rate determining step i.e. the elementary step that limits the overall rate of reactions.

than the rate law would be r=k[N][NO] it does not depend on the products.

[LHM]

what?
You are saying step 2 is the rate law? so the rate determining step i.e. the elementary step that limits the overall rate of reactions.

than the rate law would be r=k[N][NO] it does not depend on the products.

Oh oops, I'm sorry! I meant that step 2 is the rate determining step.

[LHM]

But it's highly unlikely that the answer key's wrong, which means that the rate law is rate=k[H₂][NO]², so do you or anyone else know why it's this?