The time required for a first order reaction to complete `90%` is 't'. What is the time required to complete `99%` of the same reaction?

Options

A. 2t
B. 3t
C. t
D. 4t

Answer

A

Explanation

a) `t=(2.303)/klog(1N)/(100-90)`
`=(2.303)/(42)log 10=2.303/k`
`x=(2.303)/(k)log(100)/(100-99)`
`=2.303/k log 10^(2) = (2 xx 2.303)/(k)`
`x/t=2` or `x=2t`