For the uncatalyzed reaction 2NO + O2 → 2NO2, which of the following is the correct rate law?

• A. rate = k[NO]^2
• B. rate = k[NO][O2]
• C. rate = k[NO]^2[O2]
• D. rate = k[O2]^2

Answer: (C)

Verified step by step guidance

1. Identify the reaction given: \$2NO + O_2 \rightarrow 2NO_2$.
2. Recall that the rate law expresses the rate of reaction as a function of the concentration of reactants, typically in the form \(rate = k[A]^m[B]^n\), where \(m\) and \(n\) are the reaction orders with respect to each reactant.
3. Understand that the rate law cannot be determined solely from the stoichiometric coefficients of the balanced equation; it must be determined experimentally or given in the problem.
4. For the uncatalyzed reaction, the experimentally determined rate law is \(rate = k[NO]^2[O_2]\), indicating the reaction is second order in NO and first order in \(O_2\).
5. Therefore, the correct rate law includes both reactants with their respective orders: \(rate = k[NO]^2[O_2]\).