The half-life period of a first-order reaction is 15 minutes. The amount of substance left after one hour will be,

Options

A. `1/4` of the original amount
B. `1/8` of the original amount
C. `1/16` of the original amount
D. `1/32` of the original amount

Answer

C

Explanation

Total number of half lives (n) =`(1 hour)/(15 min)=4`
Substance left after n half lives =`[A]_(0)/(2)^(n)` substance remaining after 4 half lives =`(1)/(2)^(4)=1/16`