Question

Which is the strongest acid in the following ?

• A. H₂SO₄
• B. HClO₃
• C. HClO₄
• D. H₂SO₃

Answer 1

The Correct Option is C

To determine the strongest acid among the given options, we need to consider the acid dissociation and stability of the conjugate base formed after dissociation. The general rule is: the stronger the acid, the weaker (more stable) the conjugate base.

1. Understanding the Acids:
   • H_2SO_4 (Sulfuric Acid)
   • HClO_3 (Chloric Acid)
   • HClO_4 (Perchloric Acid)
   • H_2SO_3 (Sulfurous Acid)
2. Evaluating the Strength:
   • H_2SO_4: Strong acid, completely ionizes in solution.
   • HClO_3: Strong acid, less strong compared to perchloric acid due to less oxygen stability.
   • HClO_4: Very strong acid, known for its high ionization in solution, extremely stable conjugate base ClO_4^- due to resonance and inductive effects.
   • H_2SO_3: Weak acid, does not completely ionize in solution.
3. Conclusion: HClO_4 (Perchloric Acid) is considered the strongest acid among the given options. The high electronegativity and the resonance stabilization of its conjugate base ClO_4^- make it very strong.

Therefore, the correct answer is HClO_4.