Rate constant of a reaction is $0.0693 {\min }^{-1}.$Starting with 10 mol, rate of the reaction after 10 min is

$\mathrm{K}=0.0693 {\min }^{-1}$

$t_{1/2}=\frac{0.693}{\mathrm{K}}=\frac{0.693}{0.0693}= 10 min$

${\mathrm{t}}_{100\%}2{\mathrm{t}}_{\frac{1}{2}}=2\times 10=20 \mathrm{times}$

$\mathrm{t} = 20\min \mathrm{a}=10 \mathrm{mol}$

${\mathrm{t}}_{1/2}= 10 \min \frac{\mathrm{a}}{2}=5 \mathrm{mol}$

$\mathrm{R}=\mathrm{K}\left[\mathrm{A}\right]=0.0693\times 5 {\min }^{-1}$