Answer:
Suffix -ous
Explanation:
The anions with a suffix -ite came from an oxide with one of the lower valence of the element. For example \(SO_3^-\) is sulfite and came from the \(SO_2\) where the S has a valence of +4)
Acids derived from those anions have the suffix -ous. For example \(H_2SO_3\) is the sulfurous acid.