Write the products of each reaction.

OR

Which compound in each of the following pairs will react faster in S_N2 reaction with HO^– ?

(a) ${\mathrm{CH}}_3\mathrm{Br} \mathrm{or} {\mathrm{CH}}_3\mathrm{I}$

(b) ${\left({\mathrm{CH}}_3\right)}_3\mathrm{CCl} \mathrm{or} {\mathrm{CH}}_3\mathrm{Cl}$

(c) ${\mathrm{CH}}_2=\mathrm{CHBr} \mathrm{or} {\mathrm{CH}}_2={\mathrm{CHCH}}_2{\mathrm{CH}}_2\mathrm{Cl}$