a) H₂CO₃
b) HCl
c) H₂SO₄
d) CH₃COOH
For Explanation Click Here:
Hydrochloric acid (HCl) is a strong acid because it completely dissociates into H⁺ and Cl⁻ ions in water. H₂SO₄ (sulfuric acid) is also a strong acid, but H₂CO₃ (carbonic acid) and CH₃COOH (acetic acid) are weak acids because they do not dissociate completely in water.