For a first order reaction half life is 14 sec. The time required for the initial concentration to reduce 1/8 of the value is

Options

A. 28s
B. 42s
C. `(14)^3s`
D. `(14)^2s`

Explanation

Number of half lives = n.
`[A]/[A]_0=1/2^n`
`1/8 = 1/2^3= 1/2^n` `:.n = 3`
and `n = t/(t_(1//2)) :.t =3xx14 = 42 s`