Half life of a first order reaction is 1 hour. What fraction of it will remain after 3 hour?

In the Arrhenius plot of logk versus $1 / T$ find the value of intercept on $y$ axis

For the reaction,

$$3 \mathrm{I}_{\mathrm{(aq.)}}^{-}+\mathrm{S}_2 \mathrm{O}_{8(\mathrm{aq.})}^{2-} \longrightarrow 2 \mathrm{SO}_{4(\mathrm{aq.})}^{2-}+\mathrm{I}_{3(\mathrm{aq.})}^{-}$$

rate of formation of $\mathrm{SO}_{4(\mathrm{aq.})}^{2-}$ is $0.044 \mathrm{~mol} \mathrm{~dm}^{-3} \mathrm{~s}^{-1}$.

Calculate rate of consumption of $\mathrm{I}_{(\mathrm{aq.})}^{-}$.

For a zero order reaction $\mathrm{A} \longrightarrow$ product. Conc. of $A$ decreases from $0.8 \mathrm{~mol} \mathrm{~dm}^{-3}$ to $0.2 \mathrm{~mol} \mathrm{~dm}^{-3}$ in 6 minute. What is rate constant of the reaction?