Which type of reaction is: 2AgCl(s) → 2Ag(s) + Cl₂(g) when exposed to sunlight?
(A) Thermal decomposition
(B) Electrolytic decomposition
(C) Photochemical decomposition
(D) Combination reaction
Generated by claude-sonnet-4-6 · 2026-06-26 00:53 · grounding rag
Model Answer
(C) Photochemical decomposition
In this reaction, AgCl decomposes into Ag and Cl₂ using sunlight (light energy), making it a photochemical decomposition reaction.
Source: Chemical Reactions and Equations, Chapter 1
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Explanation
- Key criterion: Identify the energy source causing decomposition. Here, sunlight (light energy) drives the reaction → photochemical decomposition.
- Thermal decomposition uses heat; electrolytic decomposition uses electricity; this reaction uses light.
- This is a classic NCERT example often cited in Exercise Q12 (decomposition using light energy).
- For MCQs, just state the correct option and give a one-line reason — no elaboration needed.