CBSE Class 12 · 2024 · Alcohols Phenols and EthersShort Answer

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Give the structure of the major product expected from each of the following reactions:
(a) reaction of ethanal with methyl magnesium bromide followed by hydrolysis
(b) hydration of but-1-ene in the presence of dilute sulphuric acid
(c) reaction of phenol with bromine water

Answer: (a) Propan-2-ol. (b) Butan-2-ol (Markovnikov). (c) 2,4,6-Tribromophenol (white ppt).

Solution

(a) Aldehyde + RMgX → 2° alcohol:

C H_{3} CHO + C H_{3} MgBr \to H_{2} O/ H^{+} C H_{3} CH (OH) C H_{3}

(b) Markovnikov hydration via the 2° carbocation:

C H_{3} C H_{2} CH = C H_{2} + H_{2} O dil. H_{2} S O_{4} C H_{3} C H_{2} CH (OH) C H_{3}

(c)

C_{6} H_{5} OH + 3B r_{2} (aq) \to 2, 4, 6 -tribromophenol ↓ + 3HBr

CBSE Class 12 Board · 2024 · Subjective

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