$A \rightarrow P$ is a first order reaction. The following graph is obtained for this reaction. $(X$-axis $=$ time: $Y$-axis $=$ conc. of $A$ ) The instantaneous rate of the reaction at point $C$ is

The rate constant of a first order reaction was doubled when the temperature was increased from 300 to 310 K . What is its approximate activation energy (in $\mathrm{kJ} \mathrm{mol}^{-1}$ )? ( $R=8.3 \mathrm{Jmol}^{-1} \mathrm{~K}^{-1}: \log 2=0.3$ )

$A \rightarrow P$ is a zero order reaction. At 298 K the rate constant of the reaction is $1 \times 10^{-3} \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}$. Initial concentration of ' $A$ ' is $0.1 \mathrm{~mol} \mathrm{~L}^{-1}$. What is the concentration of ' $A$ after 10 sec ?