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Which of the following sets of reactions are correctly described? (I) PhCHO + HCHO --conc. NaOH--> PhCH2OH + HCOONa (II) OHC-CH2-CHO --NaOH/I2--> 2 HCOONa + CHI3 (III) Cyclohexanone --1. H2NNH2/H⁺, 2. KOH/heat--> Cyclohexanol (IV) HOCH2CH2OH --PI3 (2 eq), heat--> H2C=CH2

1. I and II only
2. I, II and III
3. I, II, III and IV
4. I, II and IV

Correct answer: I and II only

Solution

Reaction I is a valid cross-Cannizzaro reaction. Reaction II correctly gives iodoform from the central CH2 and formate from the CHO groups. Reaction III is incorrect — Wolff-Kishner converts cyclohexanone to cyclohexane, not cyclohexanol (that would be reduction with NaBH4/H2). Reaction IV is debatable; PI3 converts OH to I giving 1,2-diiodoethane, and direct ethylene is not the straightforward product. Only I and II are unambiguously correct.

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