Answer
a) $HF$
b) $HCN$
c) $HClO_{2}$
Work Step by Step
a) Hydro ... "ic" acids are simple to name and consist of a hydrogen atom and the other anion. The name involves prefix “hydro-", the first syllable of the anion, and the suffix “-ic” since fluorine is the anion in this case, the name is Hydrofluoric Acid with formula $HF$.
b) Hydro ... "ic" acids are simple to name and consist of a hydrogen atom and the other anion. The name involves prefix “hydro-", the first syllable of the anion, and the suffix “-ic” since cyanide is the anion in this case, the name is Hydrocyanic Acid with formula $HCN$.
c) The chlorite ion forms chlorous acid since all polyatomic ions with "ite" suffixes form "ous" acids. So the ending is replaced with "ous" and the word "acid" is added on the end to become Sulfurous Acid. Since the chlorite ion $(ClO^{2-})$ has a charge of negative 2, crossing it down with the $H^{+}$ ion gives us $HClO_{2}$.
