Which of the following is the correct name for the acid with the formula H_2SO_3?

• A. Hydrosulfuric acid
• B. Sulfic acid
• C. Sulfurous acid
• D. Sulfuric acid

Answer: (C)

Verified step by step guidance

1. Identify the chemical formula given: \(\mathrm{H_2SO_3}\).
2. Recognize that this formula represents an oxyacid, which is an acid containing hydrogen, oxygen, and another element (in this case, sulfur).
3. Recall the naming convention for oxyacids: acids with sulfur and oxygen are named based on the number of oxygen atoms. If the acid has fewer oxygen atoms than sulfuric acid (\(\mathrm{H_2SO_4}\)), it usually ends with '-ous' instead of '-ic'.
4. Since \(\mathrm{H_2SO_3}\) has one less oxygen than sulfuric acid, its correct name is 'sulfurous acid'.
5. Confirm that 'hydrosulfuric acid' refers to \(\mathrm{H_2S}\) (hydrogen sulfide in aqueous solution), and 'sulfic acid' is not a correct name.