Question

The half-life period of a $1^{st}$ order reaction is 20 min. Calculate the time required for conc. of reaction to change from $0.16Mto0.02M$.

Answer 1

1st Order Reaction

$t_{1/2}$ = $\frac{0.693}{k}$

$k=\frac{0.693}{20}$ = $3.46\times {10}^{-2}{min}^{-1}$

$3.46\times {10}^{-2}=\frac{2.303}{t}log\frac{0.16}{0.02}$

$t=60.1min$