A proposed mechanism for the oxidation of nitric oxide to nitrogen dioxide was d
ID: 771105 • Letter: A
Question
A proposed mechanism for the oxidation of nitric oxide to nitrogen dioxide was described in Problem 12.19. Another possible mechanism for this reaction is 2 NO(g) double arrow N2O2(g) Faster, reversible N2O2 (g) + O2(g) rightarrow 2 NO2(g) Slower, rate-determining Write a balanced equation for the overall reaction. Show that this mechanism is consistent with the experimental rate law, rate = -delta [NO]/delta t = k[NO]2[O2]. Relate the rate constant k to the rate constants for the elementary reactions.Explanation / Answer
a) 2 NO + O2 --(k)--> 2NO2 .....b) From the overall reaction we see that -d(NO) / dt = k[NO]2[O2]........c) Rate is determined by slower step, so rate = k2 [N2O2] [O2] ........From reaction 1 ....k1 / k-1 = [N2O2] / [NO]^2 ......=> [N2O2] = (k1/k-1) * [NO]^2 .......putting this in rate.....=> rate = k2 * (k1 / k-1) * [NO]^2 * [O2] .....Therefore k = k2 * (k1 / k-1)