Answer
(a) $CN^-$ : Cyanide ion.
(b) ${SO_4}^{2-}$: Sulfate ion.
(c) $F^-$: Fluoride ion.
Work Step by Step
- To get the formula of a conjugate base, just remove a hydrogen from the acid, and subtract one from the charge:
(a) $HCN --\gt CN --\gt CN^-$
(b) $HS{O_4}^- --\gt S{O_4}^{-} --\gt S{O_4}^{2-}$
(c) $HF --\gt F --\gt F^-$
The name:
(a) $CN^-$ is an ion formed by the cyano group ($CN^-$), so it is the cyanide ion.
(b) $S{O_4}^{2-}$ is an ion formed by the sulfato group, so it is the sulfate ion.
(c) $F^-$ is an ion formed by a fluorine atom, so it is the fluoride ion.
