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title: "The reaction between \\(\\text{NO}(g)\\) and \\(\\text{Cl}_2(g)\\) is represented by the following equation:  \\[ 2\\text{NO}(g) + \\text{Cl}_2(g) \\rightarrow 2\\text{NOCl}(g) \\]  A chemist proposes the following two-step mechanism for the reaction:  \\[ \\text{Step 1 (fast equilibrium):}\\quad \\text{NO}(g) + \\text{Cl}_2(g) \\underset{k_{-1}}{\\overset{k_1}{\\rightleftharpoons}} \\text{NOCl}_2(g) \\] \\[ \\text{Step 2 (slow):}\\quad \\text{NOCl}_2(g) + \\text{NO}(g) \\xrightarrow{k_2} 2\\text{NOCl}(g) \\]  Based on this mechanism, which of the following is the correct rate law expression for the overall reaction in terms of elementary rate constants and reactant concentrations?"
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url: "https://nerd-notes.com/ubq/123616/"
date_modified: "2026-09-28T12:01:46+00:00"
---

# The reaction between \(\text{NO}(g)\) and \(\text{Cl}_2(g)\) is represented by the following equation:

\[ 2\text{NO}(g) + \text{Cl}_2(g) \rightarrow 2\text{NOCl}(g) \]

A chemist proposes the following two-step mechanism for the reaction:

\[ \text{Step 1 (fast equilibrium):}\quad \text{NO}(g) + \text{Cl}_2(g) \underset{k_{-1}}{\overset{k_1}{\rightleftharpoons}} \text{NOCl}_2(g) \]
\[ \text{Step 2 (slow):}\quad \text{NOCl}_2(g) + \text{NO}(g) \xrightarrow{k_2} 2\text{NOCl}(g) \]

Based on this mechanism, which of the following is the correct rate law expression for the overall reaction in terms of elementary rate constants and reactant concentrations?

The reaction between \(\text{NO}(g)\) and \(\text{Cl}_2(g)\) is represented by the following equation:

\[ 2\text{NO}(g) + \text{Cl}_2(g) \rightarrow 2\text{NOCl}(g) \]

A chemist proposes the following two-step mechanism for the reaction:

\[ \text{Step 1 (fast equilibrium):}\quad \text{NO}(g) + \text{Cl}_2(g) \underset{k_{-1}}{\overset{k_1}{\rightleftharpoons}} \text{NOCl}_2(g) \]
\[ \text{Step 2 (slow):}\quad \text{NOCl}_2(g) + \text{NO}(g) \xrightarrow{k_2} 2\text{NOCl}(g) \]

Based on this mechanism, which of the following is the correct rate law expression for the overall reaction in terms of elementary rate constants and reactant concentrations?

- **A.** \(\text{Rate} = k_2[\text{NO}][\text{Cl}_2]\)
- **B.** \(\text{Rate} = \dfrac{k_1 k_2}{k_{-1}}[\text{NO}][\text{Cl}_2]\)
- **C.** \(\text{Rate} = \dfrac{k_1 k_2}{k_{-1}}[\text{NO}]^2[\text{Cl}_2]\)
- **D.** \(\text{Rate} = \dfrac{k_{-1} k_2}{k_1}[\text{NO}]^2[\text{Cl}_2]\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123616/*