Which type of compound is H_2SO_3, and what is its correct name?

• A. Ionic compound; hydrogen sulfate
• B. Ionic compound; sulfuric acid
• C. Molecular compound; sulfurous acid
• D. Molecular compound; sulfuric acid

Answer: (C)

Verified step by step guidance

1. Identify the elements present in the compound H_2SO_3: hydrogen (H), sulfur (S), and oxygen (O).
2. Determine the type of compound by considering the elements involved: since hydrogen is bonded to a nonmetal (sulfur) and oxygen, this suggests a molecular (covalent) compound rather than an ionic compound.
3. Recognize that compounds with hydrogen and polyatomic ions containing oxygen are often acids if they release H^+ ions in solution. H_2SO_3 corresponds to an acid derived from the sulfite ion (SO_3^{2-}).
4. Recall the naming convention for oxyacids: acids derived from polyatomic ions ending in '-ite' are named with the suffix '-ous acid'. Since SO_3^{2-} is sulfite, the acid is named sulfurous acid.
5. Conclude that H_2SO_3 is a molecular compound called sulfurous acid.