The pH plays an important role in our daily life. Strength of acids and bases depends on the number of H⁺ ions and OH⁻ ions produced by these respectively. pH scale helps in predicting the strength of acids and bases by measuring hydrogen ion concentration in a solution.
The pH plays an important role in our daily life. Strength of acids and bases depends on the number of H⁺ ions and OH⁻ ions produced by these respectively. pH scale helps in predicting the strength of acids and bases by measuring hydrogen ion concentration in a solution.
Answer the following :
Generated by claude-sonnet-4-6 · 2026-06-15 06:41 · grounding stimulus
Model Answer
(a) Universal indicator is used to predict how strong an acid or base is. It shows different colours at different pH values, allowing us to determine the strength of an acid or base.
(b) Solution A (pH = 3) has the highest concentration of H⁺ ions, as lower pH indicates higher hydrogen ion concentration.
(c) Strong acids are acids that completely dissociate in water to produce a large number of H⁺ ions. Example: HCl, H₂SO₄.
Weak acids are acids that partially dissociate in water, producing fewer H⁺ ions. Example: acetic acid (CH₃COOH), carbonic acid.
Source: Chapter 2 – Acids, Bases and Salts
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Explanation
- (a) Universal indicator is the standard answer; examiners also accept "pH paper."
- (b) Remember: lower pH = higher H⁺ concentration. This is a direct 1-mark factual point — state the solution and the reason.
- (c) For 2 marks, you need both definitions with at least one example each. The key distinction is complete vs. partial dissociation. Do not write long paragraphs — two crisp definitions suffice.