Concept:Acids are classified by how completely they ionize in water. Strong acids donate all their hydrogen ions, while weak acids donate only a few.
Explanation:Nitric acid, sulphuric acid, and hydrochloric acid are all strong acids. They fully dissociate in water, giving a high concentration of
H+ ions.
Citric acid is a weak acid. It only partially dissociates, producing a lower
H+ concentration. This makes it mild and safe to eat, unlike the strong mineral acids.
The pH scale shows strength: strong acids have pH 0–3, weak acids have pH 3–6. Citric acid falls in the weak range, while the others are far lower.
Thus, among the options, only citric acid behaves as a weak acid.
Answer:A. Citric acid