Which of the following reactions is a decomposition redox reaction?

1. $2 \mathrm{~Pb}\left(\mathrm{NO}_3\right)_2(\mathrm{~s}) \rightarrow 2 \mathrm{PbO}(\mathrm{s})+4 \mathrm{NO}_2(\mathrm{~g})+\mathrm{O}_2$ (g)
2. $\mathrm{N}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{NO}(\mathrm{g})$
3. $\mathrm{Cl}_2(\mathrm{~g})+2 \mathrm{OH}(\mathrm{aq}) \rightarrow \mathrm{ClO}^{-}(\mathrm{aq})+\mathrm{Cl}^{-}(\mathrm{aq})$ $+4 \mathrm{H}_2 \mathrm{O}(l)$
4. $\mathrm{P}_4(\mathrm{~s})+3 \mathrm{OH}(\mathrm{aq})+3 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) \rightarrow \mathrm{PH}_3(\mathrm{~g}) +3 \mathrm{H}_2 \mathrm{PO}_2^{-}(\mathrm{aq})$

Solution

Redox decomposition reaction is associated with breakdown of a large molecule into smaller molecule with change in oxidation state.

Asked in: NEET 2022 (Phase 2)

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