8. Elimination Reactions

Which of the following charged nucleophiles is most reactive in $\mathrm{DMSO}$ solvent?

Which of the following molecules is a negatively charged nucleophile?

In aqueous solution, rank the following species in order of increasing nucleophilicity: $F_{-}$, ${\mathrm{Cl}}_{-}$, ${\mathrm{Br}}_{-}$, $I_{-}$.

Which of the following correctly ranks the nucleophilicity of the species $F_{-}$, ${\mathrm{Cl}}_{-}$, ${\mathrm{Br}}_{-}$, and $I_{-}$ in water from greatest to least?