The half-life period of a first order reaction is 60 minutes. What percentage will be left after 240 minutes ?

Explanation

No. of half-lives`=(240)/(60)=4,i.e., n=4`
Amount left after 4 half-lives`=([A]_(0))/(2^(4))=([A]_(0))/(16)=0*0625" of "[A]_(0)=6*25%`.