AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
H⁺(aq) ions (hydrogen ions or hydronium ions, H₃O⁺) are responsible for the acidic properties of an acid in aqueous solution.
Source: Acids, Bases and Salts, Section 2.2
The examiner expects the specific ion name — H⁺(aq) or hydronium ion (H₃O⁺). Either form is acceptable, but mentioning both shows complete understanding. Avoid writing just "hydrogen" without the ionic notation, as that will likely lose the mark.