Which of the following reactions is not an example for nucleophilic addition-elimination reaction?

1. $\mathrm{CH}_3 \mathrm{CHO}+\mathrm{NaHSO}_3 \rightleftharpoons \mathrm{CH}_3-\stackrel{\huge \mathrm{~OH} \atop |}{\underset{| \atop \huge \mathrm{H}}{\mathrm{C}}}-\mathrm{OSO}_2 \mathrm{Na}$
2. $\mathrm{CH}_3 \mathrm{CHO}+\mathrm{NH}_2 \mathrm{OH} \rightleftharpoons \mathrm{CH}_3 \mathrm{CH}=\mathrm{N}-\mathrm{OH}+\mathrm{H}_2 \mathrm{O}$
3. $\mathrm{CH}_3 \mathrm{CHO}+\mathrm{C}_6 \mathrm{H}_5 \mathrm{NHNH}_2 \rightleftharpoons \mathrm{CH}_3 \mathrm{CH}=\mathrm{N}-\mathrm{NHC}_6 \mathrm{H}_5+\mathrm{H}_2 \mathrm{O}$
4. $\mathrm{CH}_3 \mathrm{CHO}+\mathrm{NH}_3 \rightleftharpoons \mathrm{CH}_3 \mathrm{CH}=\mathrm{NH}+\mathrm{H}_2 \mathrm{O}$

Solution

Nucleophilic addition - elimination reaction is associated with elimination of $\mathrm{H}_2 \mathrm{O}$.
Here the above reaction is an addition reaction.

Asked in: NEET 2022 (Phase 2)

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