Question

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

• A. $1800s$
• B. $60min$
• C. $15min$
• D. $900s$

Answer 1

The correct option is A $1800s$

$t_{1/2}=\frac{0.693}{k}$

$k=0.0231{min}^{-1}$

Half life doesnt depend on the Initial concentration. When the initial concentration of reactant is doubled, the half life of the reaction will be 30 min = 1800 s