Question

For a first order reaction,
$A\to P$
What will be the completion time of the reaction if half life is $4min$?

• A. $4min$
• B. $8min$
• C. Infinity
• D. Insufficient data

Answer 1

The correct option is C Infinity

Since $\left[A\right]=[A{]}_0{e}^{-kt}$
Here
$[A{]}_0$ is the intial concentration.
$\left[A\right]$ is the concentration at time t

Time of completion of reaction:

At completion, reactant concentration will be zero.
$\left[A\right]=0$
$0=[A{]}_0{e}^{-kt}$
$e^{-kt}=0$
$\Rightarrow t=\infty$