Which of the following is the correct chemical formula for chlorous acid?

• A. HClO2
• B. HClO3
• C. HCl
• D. HClO

Answer: (A)

Verified step by step guidance

1. Understand that chlorous acid is an oxyacid of chlorine, where chlorine is bonded to oxygen and hydrogen atoms.
2. Recall that the naming of oxyacids depends on the number of oxygen atoms: 'chlorous acid' corresponds to chlorine with two oxygen atoms.
3. Recognize the general formula for chlorous acid is HClO\_2, where H is hydrogen, Cl is chlorine, and O\_2 indicates two oxygen atoms.
4. Compare the given options with the general formula: HClO\_3 is chloric acid, HCl is hydrochloric acid, and HClO is hypochlorous acid.
5. Conclude that the correct formula for chlorous acid is HClO\_2 based on the number of oxygen atoms and the acid naming conventions.