Q1. [1] § 2.1 UNDERSTANDING THE CHEMICAL PROPERTIES OF ACIDS AND BASES § 2.3 HOW STRONG ARE ACID OR BASE SOLUTIONS?
The table below has information regarding pH and the nature (acidic/basic) of four different solutions. Which one of the options in the table is correct ?
- (a) Lemon juice, Orange, 3, Basic
- (b) Milk of magnesia, Blue, 10, Basic
- (c) Gastric juice, Red, 6, Acidic
- (d) Pure water, Yellow, 7, Neutral
Previously asked in CBSE board exam
2023 31/1/1 Q4
Generated by claude-sonnet-4-6 · 2026-06-15 06:46 · grounding rag
Model Answer
(b) Milk of magnesia, Blue, 10, Basic.
Milk of magnesia (Mg(OH)₂) is a base with pH = 10, so it turns pH paper blue and is basic in nature. This is the only fully correct row.
Source: Chapter 2, Section 2.3
Explanation
- Option (a) is wrong: lemon juice is acidic, not basic.
- Option (c) is wrong: gastric juice has pH ≈ 2, not 6 (it is strongly acidic, turning pH paper red/orange).
- Option (d) is wrong: pure water turns pH paper green, not yellow; pH = 7 (neutral) is correct but the colour is wrong.
- Option (b) is entirely correct — milk of magnesia is a base, pH 10, blue on pH paper.
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