Which one of the following reactions is an example of decomposition reaction?
[amp_mcq option1=”CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(g)” option2=”2AgCl(s) Sunlight → 2Ag(s) + Cl₂(g)” option3=”CuO + H₂ Heat → Cu + H₂O” option4=”Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s)” correct=”option2″]
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UPSC NDA-1 – 2022
Option B, $2\text{AgCl(s)} \text{ Sunlight} \rightarrow 2\text{Ag(s)} + \text{Cl}_2\text{(g)}$, shows silver chloride (a single compound) breaking down into silver and chlorine (simpler substances) upon exposure to sunlight. This is a classic example of photolytic decomposition.
Option C is a reduction reaction, specifically the reduction of copper(II) oxide by hydrogen.
Option D is a displacement reaction, where iron displaces copper from copper sulphate solution.