In a zero order reaction for every 10^ rise of temperature, the...

For $10^{\circ}$ rise in temperature, $n=1$ so rate $=2^n=2^1=2$ When temperature is increased from $10^{\circ} \mathrm{C}$ to $100^{\circ} \mathrm{C}$, change in temperature $=100-10=90^{\circ} \mathrm{C}$, i.e., $n=9$ So, rate $=2^9=512$ times Alternate method With every $10^{\circ}$ rise in temperature, rate becomes double, so $\frac{r^{\prime}}{r}=2^{\left(\frac{100-10}{10}\right)}=2^9=512$ times.