Which of the following is the correct chemical formula for perchloric acid formed in aqueous solution?

• A. HClO2
• B. HClO4
• C. HClO3
• D. HCl

Answer: (B)

Verified step by step guidance

1. Understand that perchloric acid is an oxyacid of chlorine, where chlorine is bonded to oxygen atoms and hydrogen is attached to one of the oxygens, forming an acidic hydrogen.
2. Recall the naming convention for chlorine oxyacids: the suffix '-ic' corresponds to the oxyacid with the highest number of oxygen atoms, while '-ous' corresponds to fewer oxygens. For example, chlorous acid is HClO2, chloric acid is HClO3, and perchloric acid has even more oxygens.
3. Identify that 'perchloric acid' means the chlorine atom is bonded to four oxygen atoms, making the formula HClO4.
4. Verify that the other options do not match the definition of perchloric acid: HClO2 is chlorous acid, HClO3 is chloric acid, and HCl is hydrochloric acid (no oxygen).
5. Conclude that the correct chemical formula for perchloric acid in aqueous solution is HClO4.