Resolved Question

Need Help With This Rate Equation Question?

Following rate equation was determined from reaction
NO2+CO=NO+CO2:

Rate=k[NO2][CO]

The following mechanism has been proposed:

NO2 + CO=ONOCO (slow)
ONOCO= NO+CO2 (fast)

Determine if this mechanism is consistent with rate equation?
I wasn't fully sure if I done this correct but since the first reaction in the mechanism is slow it's the rate determining step and so the rate must be Rate=k[NO2][CO].
Can someone confirm this or do I need more info?

by joeyeehu...
Best Answer - Chosen by Asker

You are right in saying that the slow step is the rate determining step and you can write the rate equation from it. But the question is whether the mechanism proposed is consistent with the rate equation?

To confirm this, just add the two elementary steps proposed. You will get the overall equation. This shows that the mechanism proposed is consistent with the rate equation.

ONOCO is called the intermediate and it will not feature in the overall equation. If you get the intermediate in the overall equation, then the mechanism proposed is not correct.