Question

The correct difference between first and second-order reaction is that:

• A. A first order reaction can be catalysed; a second order reaction cannot be catalysed
• B. The half-life of a first- order reaction doe not depend on $\left[A_0\right]$; the half-life of a second - order reaction depend on $\left[A_0\right]$
• C. The rate of a first-order reaction does not depend on reaction concentrations; the rate of a second order reaction does depend on reactant concentrations
• D. The rate of a first-order reaction does depend on reactant concentration; the rate of a second order reaction does not depend on reactant concentrations.

Answer 1

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

For first-order reaction:
$t_{1/2}=\frac{0.693}{k}$
(independent of initial concentration)

For second-order reaction:
$t_{1/2}=\frac{1}{k\times \text{Initial concentratin}}$
(depends of initial concentration)