Identify product [A], [B] and [C] in the following reaction sequence. CH3-C CH [H2]Pd/C [A] [(ii) Zn, H2O](i) O3 [B] + [C]
- [A]: CH3-CH=CH2, [B]: CH3CHO, [C]: CH3CH2OH
- [A]: CH3-CH=CH2, [B]: CH3CHO, [C]: HCHO
- [A]: CH3CH2CH3, [B]: CH3CHO, [C]: HCHO
- [A]: CH2=CH2, [B]: H3C- O \|C-CH3, [C]: HCHO
Answer
(2) [A]: CH3-CH=CH2, [B]: CH3CHO, [C]: HCHO
Solution
Step 1: as per NCERT, an alkyne with a calculated amount of H2 over palladised charcoal (Pd/C, partially deactivated) is reduced only up to the alkene stage:
CH3-C CH + H2 Pd/C CH3-CH=CH2 = [A] (propene)
Step 2: reductive ozonolysis cleaves the C=C bond and puts a C=O on each carbon:
CH3-CH=CH2 [(ii) Zn, H2O](i) O3 CH3CHO + HCHO
[B] = CH3CHO (ethanal), [C] = HCHO (methanal).
Answer: (2)