Question

The correct difference between first and second order reactions is that

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• A. 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
• B. 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
• C. a first-order reaction can be catalyzed; a second-order reaction cannot be catalyzed
• D. the half-life of a first-order reaction does not depend on $\left[A_0\right]$; the half-life of a second-order reaction does depend on $\left[A_0\right]$

Answer 1

The correct option is D the half-life of a first-order reaction does not depend on $\left[A_0\right]$; the half-life of a second-order reaction does depend on $\left[A_0\right]$

In both first and second order reaction, the rate depends on the reactant concentration.

Both first and second order reactions can be catalyzed.

For first order reaction,
$t_{1/2}=\frac{0.693}{k}$,

Thus, half life period is independent of initial concentration of reactant.

For second order reaction, $t_{1/2}=\frac{1}{k\left[A_0\right]}$
Thus, half life period depends on initial concentration of reactant.

Hence, option (d) is correct.