Half-life period of a first-order reaction is `1386` seconds. The specific rate constant of the reaction is

Options

A. `0.5xx10^(-2)s^(-1)`
B. `0.5x10^(-3)s^(-1)`
C. `5.0xx10^(-2)s^(-1)`
D. `5.0xx10^(-3)s^(-1)`

Answer

B

Explanation

For the first order reaction
`t_(1//2)=(0.693)/(k)`
Thus,
`k=(0.693)/(t_(1//2))`
`=(0.693)/(1386s)=0.0005s^(-1)`
`0.5xx10^(-3)s^(-1)`