Question

Half-life of a reaction becomes half when initial concentration of reactants are made double. The order of reaction will be

• A. 1
• B. 2
• C. 0
• D. 3

Answer 1

Answer: (B)

$\text{t}_{\frac{1}{2}} \propto \frac{1}{\text{C}_{0}^{\text{o} \text{r} \text{d} \text{e} \text{r} \, - 1}}$ where C₀=initial conc.
^{Now as $ \, \, \text{t}_{1/2} \propto \text{C}_{0}^{1 - \text{o} \text{r} \text{d} \text{e} \text{r}}$}
According to the question, half life becomes half on doubling concentration, i.e., $\text{t}_{1 / 2} \, \propto \, \text{C}_{0}^{- 1}$
∴ on comparing we get order = 2