A chemical reaction was carried out at 300 K and 280 K . The rate...

For every $10^{\circ} \mathrm{C}$ rise, rate constant gets doubled. Hence, for every $20^{\circ} \mathrm{C}$ rise, rate constant will be 4 times. Therefore, according to the given statement, Temperature $\quad 280 \mathrm{~K} \quad 300 \mathrm{~K}$ Rate constant $\quad \mathrm{k}_2 \quad \mathrm{k}_1$\left(4 \mathrm{k}_2\right)$Thus,$\quad \mathrm{k}_1=4 \mathrm{k}_2 \Rightarrow \mathrm{k}_2=0.25 \mathrm{k}_1