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title: "A proposed mechanism for the gas-phase reaction \\(2\\,\\text{NO}_2\\text{(g)} + \\text{F}_2\\text{(g)} \\rightarrow 2\\,\\text{NO}_2\\text{F(g)}\\) consists of the following two elementary steps:  Step 1: \\(\\text{NO}_2\\text{(g)} + \\text{F}_2\\text{(g)} \\rightarrow \\text{NO}_2\\text{F(g)} + \\text{F(g)}\\) (slow) Step 2: \\(\\text{NO}_2\\text{(g)} + \\text{F(g)} \\rightarrow \\text{NO}_2\\text{F(g)}\\) (fast)  Which of the following claims and justifications best explains why the experimentally observed rate law is \\(\\text{Rate} = k[\\text{NO}_2][\\text{F}_2]\\)?"
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url: "https://nerd-notes.com/ubq/119323/"
date_modified: "2026-08-19T12:39:49+00:00"
---

# A proposed mechanism for the gas-phase reaction \(2\,\text{NO}_2\text{(g)} + \text{F}_2\text{(g)} \rightarrow 2\,\text{NO}_2\text{F(g)}\) consists of the following two elementary steps:

Step 1: \(\text{NO}_2\text{(g)} + \text{F}_2\text{(g)} \rightarrow \text{NO}_2\text{F(g)} + \text{F(g)}\) (slow)
Step 2: \(\text{NO}_2\text{(g)} + \text{F(g)} \rightarrow \text{NO}_2\text{F(g)}\) (fast)

Which of the following claims and justifications best explains why the experimentally observed rate law is \(\text{Rate} = k[\text{NO}_2][\text{F}_2]\)?

A proposed mechanism for the gas-phase reaction \(2\,\text{NO}_2\text{(g)} + \text{F}_2\text{(g)} \rightarrow 2\,\text{NO}_2\text{F(g)}\) consists of the following two elementary steps:

Step 1: \(\text{NO}_2\text{(g)} + \text{F}_2\text{(g)} \rightarrow \text{NO}_2\text{F(g)} + \text{F(g)}\) (slow)
Step 2: \(\text{NO}_2\text{(g)} + \text{F(g)} \rightarrow \text{NO}_2\text{F(g)}\) (fast)

Which of the following claims and justifications best explains why the experimentally observed rate law is \(\text{Rate} = k[\text{NO}_2][\text{F}_2]\)?

- **A.** Step 1 determines the overall rate law because it has a higher activation energy than Step 2, making it the rate-determining step that limits the overall reaction rate.
- **B.** Step 1 determines the overall rate law because \(\text{F}_2\text{(g)}\) is completely consumed in Step 1, making it the limiting reactant of the reaction mechanism.
- **C.** Step 2 determines the overall rate law because its lower activation energy enables molecules to overcome the energy barrier more rapidly.
- **D.** Step 2 determines the overall rate law because the fast consumption of the intermediate \(\text{F(g)}\) drives the overall reaction forward.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119323/*