Which of the following chemical formulas represents perchloric acid?

• A. HClO_4
• B. HClO
• C. HClO_3
• D. HClO_2

Answer: (A)

Verified step by step guidance

1. Understand that perchloric acid is a strong acid derived from the perchlorate ion, which contains chlorine and oxygen atoms in the highest oxidation state of chlorine.
2. Recall the series of oxyacids of chlorine: hypochlorous acid (HClO), chlorous acid (HClO_2), chloric acid (HClO_3), and perchloric acid (HClO_4). The number of oxygen atoms increases as you move from hypo- to per- prefixes.
3. Identify that the prefix 'per-' indicates the acid with the highest number of oxygen atoms bonded to chlorine in this series.
4. Match the chemical formulas given with their corresponding acids: HClO is hypochlorous acid, HClO_2 is chlorous acid, HClO_3 is chloric acid, and HClO_4 is perchloric acid.
5. Conclude that the formula representing perchloric acid is \(\mathrm{HClO_4}\) because it has the highest number of oxygen atoms among the options.