Answer
The formulas for the compounds are listed below;
a) $H_{3}PO_{4}$
b) $HBr$
c) $H_{2}SO_{3}$
Work Step by Step
a) The phosphate ion forms phosphoric acid since all polyatomic ions with "ate" suffixes form "ic" acids. So the ending is replaced with "ic" and the word "acid" is added on the end to become Phosphoric Acid. Since the phosphate ion $(PO_{4}^{3-})$ has a charge of negative 3, crossing it down with the $H^{+}$ ion gives us $H_{3}PO_{4}$.
b) Hydro ... "ic" acids are simple to name and consist of a hydrogen atom and the other anion. The name involves the prefix “hydro-“, the first syllable of the anion, and the suffix “-ic” since bromine is the anion in this case, the name is Hydrobromic Acid with formula $HBr$.
c) The sulfite ion forms sulfurous 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 sulfite ion $(SO_{3}^{2-})$ has a charge of negative 2, crossing it down with the $H^{+}$ ion gives us $H_{2}SO_{3}$.
