Answer
Classification of Acids Based on Protic Nature
HI (Hydroiodic acid)
HI is a monoprotic acid. It contains only one ionizable hydrogen atom.
It dissociates in water as:
HI → H⁺ + I⁻
✅ This is not a polyprotic acid.
HNO₃ (Nitric acid)
HNO₃ is also a monoprotic acid. It donates only one proton per molecule.
HNO₃ → H⁺ + NO₃⁻
✅ This is not a polyprotic acid.
HCl (Hydrochloric acid)
HCl is a strong, monoprotic acid. It releases one proton:
HCl → H⁺ + Cl⁻
✅ This is not a polyprotic acid.
H₂SO₄ (Sulfuric acid)
H₂SO₄ is a polyprotic acid, specifically a diprotic acid.
It can donate two protons in a two-step dissociation:
H₂SO₄ → H⁺ + HSO₄⁻
HSO₄⁻ ⇌ H⁺ + SO₄²⁻
❌ This is a polyprotic acid.