Question

If 60 % of a first order reaction was completed in 60 min then half life period is ?

Answer 1

Use the relation.
$\frac{t_{1/2}}{t_{60\%}}=\left(\frac{0.3}{\left(log\frac{100}{100-60}\right)}\right)$
$t_{1/2}\frac{60min\times 0.3}{(log10-log4)}=\frac{60min\times 0.3}{0.4}$ = $45$min