Which of the following alkyl halides reacts fastest with trimethylamine in an $S_{\mathrm{N\; 2}}$ reaction?

Which one of the following compounds forms a diazonium ion when treated with ${\mathrm{Na}}_{2}O$ in aqueous $H_2\mathrm{Cl}$?

Which of the following compounds would react more rapidly with a nucleophile in an $S_{\mathrm{N}}2$ reaction?

Which of the following compounds is the least reactive toward $\mathrm{nucleophilic} \mathrm{addition}-\mathrm{elimination} \mathrm{reactions}$?

Which of the following reactions is classified as a nucleophilic substitution reaction?

Which of the following is a substitution reaction?

Which of the following alkyl halides is the most reactive substrate in an $E_2$ reaction?

Which of the following is the best nucleophile in ${\mathrm{CH}}_3\mathrm{OH}$ (methanol) solvent?

In a typical nucleophilic substitution reaction, what type of bond cleavage occurs when the leaving group departs from the substrate?