Half life of a first order reaction is 900 minute at 400 K , find its half life at 300 K ?

$$ \left(\frac{\mathrm{E}_{\mathrm{a}}}{2.303 \mathrm{R}}=1.3056 \times 10^3\right) $$

Rate law for the reaction,

$$ \mathrm{C}_2 \mathrm{H}_5 \mathrm{I}_{(\mathrm{g})} \longrightarrow \mathrm{C}_2 \mathrm{H}_{4(\mathrm{~g})}+\mathrm{HI}_{(\mathrm{g})} \text { is } \mathrm{r}=\mathrm{k}\left[\mathrm{C}_2 \mathrm{H}_5 \mathrm{I}\right] $$

What is the order and molecularity of this reaction?

In a first order reaction $60 \%$ of the reactant converts into product in 45 minute. Calculate rate constant of the reaction.

For the reaction,

$$\mathrm{CH}_3 \mathrm{Br}_{(\mathrm{aq})}+\mathrm{OH}_{(\mathrm{aq})}^{-} \longrightarrow \mathrm{CH}_3 \mathrm{OH}_{(\mathrm{aq})}+\mathrm{Br}_{(\mathrm{aq})}^{-}$$

rate of consumption of $\mathrm{OH}_{(\mathrm{aq})}^{-}$is $\mathrm{x} \mathrm{mol} \mathrm{dm}{ }^{-3} \mathrm{~s}^{-1}$ What is the rate of formation of $\mathrm{Br}_{(9 q)}^{-}$?