The rate constant and half - life of a first order reaction are related to each other as _____.

Options

A. `t_(1//2)=(0.693)/k`
B. `t_(1//2)=0.693`
C. `k=0.693t_(1//2)`
D. `kt_(1//2)=1/0.693`

Answer

A

Explanation

For first order reaction, `k=(2.303)/t"log "[[Ag]]/[[A]]`
At `t=t_(1//2),[A]=[A_0]//2`
`k=(2.303)/t_(1//2)(log) [[A_0]]/[[A_0]],k=(2.303)/t_(1//2)log2`
`k=(0.693)/t_(1//2)or t_(1//2)=(0.693)/k`