The hydrolysis of an ester in acid medium is first order reaction. Half life period of a first order reaction is 20 seconds. How much time will it take to complete 90% of the reaction?

Explanation

`k=(0.693)/t_(1/2)=0.693/20=0.3465s^(-1)`
If initial concentration`[R]_0`=100,[R]=100-90=10
`thereforet=2.303/k log ([R]_0)/([R])2.303/0.03465 log 100/10=(2.303xx1)/0.03465=66.46`seconds