Question

$A \rightarrow B$
The above reaction is of zero order. Half life of this reaction is $50 \min$. The time taken for the concentration of $A$ to reduce to one-fourth of its initial value is ____ $\min$.
(Nearest integer)

Answer 1

Assume reaction starts with 1 mole $A$
$\left( t _{1 / 2}=\frac{ a }{2 k }, K =\frac{1}{2 \times 50}\right.$
For $75 \%$ completion
$ a -\frac{ a }{4}= kt $
$ t =\frac{3}{4} \frac{ a }{ k }=\frac{3}{4} \times \frac{100}{ a }=75$