Which formula correctly represents chlorous acid?

• A. $HClO$
• B. $HCl{O}_3$
• C. $HCl{O}_2$
• D. $HCl{O}_4$

Answer: (C)

Verified step by step guidance

1. Understand that chlorous acid is an oxyacid of chlorine, where chlorine is bonded to oxygen atoms and hydrogen is attached to one of the oxygens.
2. Recall the naming convention for chlorine oxyacids: 'hypochlorous acid' corresponds to HClO, 'chlorous acid' corresponds to HClO₂, 'chloric acid' corresponds to HClO₃, and 'perchloric acid' corresponds to HClO₄.
3. Identify that the subscript number after oxygen in the formula indicates how many oxygen atoms are bonded to chlorine in the acid.
4. Match the name 'chlorous acid' to the formula with two oxygen atoms, which is HClO₂.
5. Confirm that the correct formula for chlorous acid is \(\text{HClO}_2\).