A reaction that is of the first order with respect to reactant A has a rate constant `6 "min"^(-1)`. If we start with `[A] = 0.05 "mol" 1^(-1)`, when would `[A]` reach the value `0.05 mol 1^(-1)`

Options

A. `0.384 min`
B. `0.15 min`
C. `3 min`
D. `3.84 min`

Answer

A

Explanation

We know that for first order kinetics
`k = (2.303)/(t) "log"(a)/(a-x)`
`(a-x) = 0.05 mol L^(-1), 6 = (2.303)/(t) "log"(0.5)/(0.05)`
or `t = (2.303)/(6) "log"(0.5)/(0.05) = (2.303)/(6) = 0.384 min`