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