Science — AI-generated practice question

HCl produces more H⁺ ions than CH₃COOH of the same concentration.

HCl is a strong acid — it ionises completely in water:
$$\text{HCl} \rightarrow \text{H}^+\text{(aq)} + \text{Cl}^-\text{(aq)}$$

CH₃COOH is a weak acid — it ionises only partially in water, producing fewer H⁺ ions:
$$\text{CH}_3\text{COOH} \rightleftharpoons \text{CH}_3\text{COO}^-\text{(aq)} + \text{H}^+\text{(aq)}$$

This tells us that acid strength depends on the degree of ionisation — acids that produce more H⁺ ions in solution are strong acids, and acids that produce fewer H⁺ ions are weak acids. This difference can be detected using a universal indicator, which shows a lower pH for HCl than for acetic acid of the same concentration.

Source: Chapter 2, Section 2.3; Chapter 4, Section 4.4.2

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• The key concept is degree of ionisation: HCl ionises completely (strong acid); CH₃COOH ionises partially (weak acid).
• Write the ionisation equations — examiners award marks for these.
• The reversible arrow (⇌) for acetic acid is important; it signals partial ionisation.
• Mention that a universal indicator/pH scale can distinguish them experimentally — this links theory to Activity 4.7 in the textbook.
• Do not confuse concentration with strength; both acids here have the same concentration but different strengths.