Topic: Integrated rate equations and half-life (zero and first order)· Chemical Kinetics

The correct difference between first- and second-order reactions is that

1. the rate of a first-order reaction does not depend on reactant concentrations; the rate of a second-order reaction does depend on reactant concentrations

2. a first-order reaction can be catalyzed; a second-order reaction cannot be catalyzed

3. the half-life of a first-order reaction does not depend on [A]\(_0\); the half-life of a second-order reaction does depend on [A]\(_0\)

4. the rate of a first-order reaction does depend on reactant concentrations; the rate of a second-order reaction does not depend on reactant concentrations

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Answer: 3. the half-life of a first-order reaction does not depend on [A]\(_0\); the half-life of a second-order reaction does depend on [A]\(_0\)

For first order, \(t_{1/2}=0.693/k\), independent of \([\mathrm{A}]_0\). For second order, \(t_{1/2}=1/(k[\mathrm{A}]_0)\), which depends on the initial concentration.

Rates of both orders depend on reactant concentration (rate = \(k[\mathrm{A}]\) and \(k[\mathrm{A}]^2\)), so options 1 and 4 are wrong. Catalysis does not depend on the order, so option 2 is wrong.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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The correct difference between first- and second-order reactions is that

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