Q1. [1] § 2.1 UNDERSTANDING THE CHEMICAL PROPERTIES OF ACIDS AND BASES § 2.4 MORE ABOUT SALTS
Consider the following reactions :
(i) Dilute hydrochloric acid reacts with sodium hydroxide.
(ii) Magnesium oxide reacts with dilute hydrochloric acid.
(iii) Carbon dioxide reacts with sodium hydroxide.
It is found that in each case :
- (A) Salt and water is formed.
- (B) Neutral salts are formed.
- (C) Hydrogen gas is formed.
- (D) Acidic salts are formed.
Previously asked in CBSE board exam
2025 31/1/1 Q4
Generated by claude-sonnet-4-6 · 2026-06-15 06:43 · grounding rag
Model Answer
(A) Salt and water is formed.
- HCl + NaOH → NaCl + H₂O (neutralisation)
- MgO + 2HCl → MgCl₂ + H₂O (metal oxide + acid)
- CO₂ + 2NaOH → Na₂CO₃ + H₂O (non-metallic oxide + base)
In each case, a salt and water are produced.
Explanation
The key concept tested is that acid-base reactions, metal oxide + acid reactions, and non-metallic oxide + base reactions all yield salt + water. Option B is wrong because Na₂CO₃ is not a neutral salt. Option C is wrong — no hydrogen gas is released in any of these three reactions. Option D is incorrect as acidic salts are not necessarily formed here.
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