Which of the following statements are correct?

1. AIn ${\mathrm{S}}_{\mathrm{N}}2$ with $\mathrm{NaI}$ in acetone, the order of reactivity is $\mathrm{CH}{}_3\mathrm{Br}>\mathrm{CH}{}_3\mathrm{CH}{}_2\mathrm{Br}>(\mathrm{CH}{}_3){}_2\mathrm{CHBr}$.
2. BIn ${\mathrm{S}}_{\mathrm{N}}1$ solvolysis in aqueous ethanol, the order of reactivity is $(\mathrm{CH}{}_3){}_3\mathrm{CBr}>(\mathrm{CH}{}_3){}_2\mathrm{CHBr}>\mathrm{CH}{}_3\mathrm{CH}{}_2\mathrm{Br}$.
3. CIn ${\mathrm{S}}_{\mathrm{N}}2$ with iodide, $\mathrm{CH}{}_3\mathrm{CH}{}_2\mathrm{F}$ reacts faster than $\mathrm{CH}{}_3\mathrm{CH}{}_2\mathrm{I}$.
4. DBenzyl chloride can react by both ${\mathrm{S}}_{\mathrm{N}}1$ and ${\mathrm{S}}_{\mathrm{N}}2$ paths, whereas chlorobenzene reacts by neither under ordinary conditions.