Chemistry

Chemistry

Problem

A proposed mechanism for the decomposition of ozone is shown. Step 1 NO(g) + O3(g) → NO2(g) + O2(g) (slow) Step 2 NO2(g) + O(g) → NO(g) + O2(g) (fast) Which of the following is the rate law that is consistent with this mechanism? a) k[NO]2[O3]k[\text{NO}]^{2}[\text{O}_3] b) k[O3]2k[\text{O}_3]^{2} c) k[NO][O3]k[\text{NO}][\text{O}_3] d) k[NO2][O3]k[\text{NO}_2][\text{O}_3]
Intuitive explanation

The rate law depends on the rate-determining step — the slowest step controls how fast the overall reaction proceeds. Since Step 1 is slow, write the rate law directly from its reactants: rate = k[k[NO][][O3_3].Don′tincludetheintermediateNO. Don't include the intermediate NO_2$ from Step 2, since intermediates are produced and consumed within the mechanism and don't appear in the final rate law.

Intuitive explanation

The rate law depends on the rate-determining step — the slowest step controls how fast the overall reaction proceeds. Since Step 1 is slow, write the rate law directly from its reactants: rate = k[k[NO][][O3_3].Don′tincludetheintermediateNO. Don't include the intermediate NO_2$ from Step 2, since intermediates are produced and consumed within the mechanism and don't appear in the final rate law.

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