Question

The half life of a first order reaction is 30 min and the initial concentration of the reactant is 0.1 M .If the initial concentration of reaction is doubled,then half life of the reaction will be

• A. 1800 s
• B. 30 min
• C. 15 min
• D. 900 s

Answer 1

The correct option is B 30 min

$\begin{array}{c}\text{Half life of}{1}^{\text{st}}\text{order reaction}\\ \begin{array}{c}{t}_{1/2}=\frac{0.693}{K}\\ \therefore \text{half life is dependent only on}\\ \text{rate constant}\\ \therefore \text{half life is}30\text{min.}\end{array}\end{array}$