Q1. [1]
A metal, 'X', on treatment with sodium hydroxide liberates a gas 'G'. It also liberates the same gas, 'G' on treatment with dilute sulphuric acid. Based on above information, 'X' and 'G' respectively are
- A Copper and Sulphur dioxide
- B Zinc and Sulphur dioxide
- C Zinc and Hydrogen
- D Copper and Hydrogen
Previously asked in CBSE board exam
2025 31/5/1 Q4
Generated by claude-sonnet-4-6 · 2026-06-15 06:48 · grounding rag
Model Answer
Option C: Zinc and Hydrogen
Zinc reacts with NaOH to give Na₂ZnO₂ + H₂, and with dilute H₂SO₄ to give ZnSO₄ + H₂. Thus X = Zinc, G = Hydrogen.
Explanation
Zinc is an amphoteric metal — it reacts with both acids and bases to release hydrogen gas. Copper does not react with NaOH or dilute H₂SO₄, so options A and D are eliminated. Sulphur dioxide is not produced in these reactions, eliminating B. Examiners expect you to recall the reaction: 2NaOH + Zn → Na₂ZnO₂ + H₂↑, as given in Activity 2.4 of Chapter 2.
If a question refers to an image, map, graph or diagram that is not shown here, open the Study Guide single page app, go to
Library and find the actual CBSE question paper. The original papers are also available on the CBSE website:
cbse.gov.in.