25% of a first order reaction is completed in 30 min . Find the time required for completion of 50% of the reaction.

Explanation

`k=(2.303)/(t)log.(a)/(a-x)=(2.303)/(30)log.(a)/(a-0.25a)`
`=9.59xx10^(-3)"min"^(-1)`
`t_(50%)=(0.693)/(k)=(0.693)/(9.59xx10^(-3))=72.27min`