The following mechanism has been proposed for the reaction
of NO ...

Question

The following mechanism has been proposed for the reaction
of NO with H2 to form N2O and H2O:
NO1g2 + NO1g2¡N2O21g2
N2O21g2 + H21g2¡N2O1g2 + H2O1g2
(d) The observed rate law is rate = k3NO423H24. If
the proposed mechanism is correct, what can we conclude
about the relative speeds of the first and second reactions?

Accepted Answer

Hello everyone today. We are being told that there is a reaction between nitric oxide and carbon monoxide. That takes place in two steps. The first step involves two nitric oxide molecules coming together. And the second step involves one nitrous oxide and one carbon monoxide molecule coming together. And so the first thing I wanna do is you want to write the rate laws for each step. So for step one the rate law for this reaction would just simply be that the rate is equal to some constant K. That's times are multiplied by nitric oxide, N. 02. And since there's two of them coming together, we square it for our second step. So step to the first step one the rate would be equal to K. Or some constant times a three molecule times a carbon monoxide molecule. And so the rate law. The second step involves this N. 03 and this C. O molecule. And if it were the rate determining step, then C. O. Or carbon monoxide would be the term in the actual rate law which we saw from the question stem that the rate is equal to K. Times nitric oxide squared. And so since there actually is no C. O. Or carbon monoxide in the rate law, the first step step, one must be the rate law. So the first step must be the slow step. While the second step must be the fast step overall, I hope this helped. And until next time

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