Question

The rate constant for a first order reaction is $20 \min ^{-1}$ The time required for the initial concentration of the reactant to reduce to its $\frac{1}{32}$ level is ___$\times 10^{-2} \min$ (Nearest integer)
(Given: $\ln 10=2.303$ $\log 2=0.3010$ )

Answer 1

C=2nCo​​=32Co​​
n=5
t=5t1/2​
=205×0.693​=40.693​
=0.17325min=17.325×10−2min
So, the correct answer is 17.