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Which of the following reaction statements are correctly described? (I) Ph-CHO + HCHO --(conc. NaOH)--> Ph-CH2OH + HCOONa (Cannizzaro reaction) (II) OHC-CH2-CHO --(NaOH, I2)--> 2 HCOONa + CHI3 (iodoform followed by Cannizzaro) (III) Cyclohexanone --(1. H2N-NH2/H+, 2. OH-/heat)--> Cyclohexane (Wolff-Kishner reduction) (IV) HO-CH2-CH2-OH --(PI3, 2 eq., heat)--> CH2=CH2

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

Correct answer: I, II and III only

Solution

Reactions I (crossed Cannizzaro), II (iodoform + Cannizzaro of glyoxal), and III (Wolff-Kishner reduction of cyclohexanone to cyclohexane) are all correctly described. Reaction IV: PI3 replaces -OH with -I giving ICH2-CH2I (1,2-diiodoethane); simple PI3 does not directly give ethylene, so IV is incorrect.

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