Which type of compound is HNO2, and what is its correct name according to IUPAC nomenclature?

• A. Ionic compound; nitric acid
• B. Ionic compound; nitrous acid
• C. Molecular compound; nitrous acid
• D. Molecular compound; nitric acid

Answer: (C)

Verified step by step guidance

1. Identify the elements present in HNO2: hydrogen (H), nitrogen (N), and oxygen (O). Since it contains nonmetals only, it is a molecular compound rather than an ionic compound.
2. Recognize that HNO2 is an oxoacid, which is an acid containing hydrogen, oxygen, and another element (in this case, nitrogen).
3. Recall the naming convention for oxoacids: acids with the suffix '-ous' correspond to the anion ending in '-ite', and acids with the suffix '-ic' correspond to the anion ending in '-ate'.
4. Determine the related anions: nitrite ion is NO2⁻ and nitrate ion is NO3⁻. Since HNO2 corresponds to the nitrite ion, the acid name uses the '-ous' suffix.
5. Conclude that HNO2 is a molecular compound named nitrous acid according to IUPAC nomenclature.