Question

The compound that behaves as an acid in H2SO4 (that is, it is a stronger acid than H2SO4 and can protonate it) is:

• A. CH3COOH
• B. HNO3
• C. HClO4
• D. H2O

Hint:

The stronger acid protonates the weaker one; HClO4 outranks H2SO4.

Answer 1

The Correct Option is C

Approximate pKa: CH3COOH ~4.8, H2O ~15.7, HNO3 ~-1.4, HClO4 ~-10, H2SO4 ~-3. HClO4's much lower pKa than H2SO4 confirms it as the stronger acid, so it donates the proton.

\[\boxed{HClO_4}\]