Acetaldehyde cyanohydrin on acid hydrolysis yields
Correct answer: C. Lactic acid
- A. Tartaric acid
- B. Propanoic acid
- C. Lactic acid
- D. Valeric acid
Explanation
When acetaldehyde cyanohydrin, CH₃CH(OH)CN, undergoes acid hydrolysis, it undergoes two key reactions:Cleavage of the cyanohydrin group: The CN bond breaks, releasing hydrogen cyanide (HCN) and leaving behind a 2-hydroxypropionic acid molecule (CH₃CH(OH)COOH).Stereochemistry: Acetaldehyde cyanohydrin exists as a racemic mixture of two enantiomers (mirror images) due to the asymmetric carbon atom bonded to the hydroxyl and cyano groups. During hydrolysis, both enantiomers retain their configurations, resulting in a racemic mixture of 2-hydroxypropionic acid, also known as lactic acid.
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About Aldehydes and Ketones
Aldehydes and ketones contain the polar carbonyl group, but aldehydes are generally more readily oxidised and more reactive than ketones. Coverage includes preparation by oxidation or reduction routes, nucleophilic addition of reagents such as hydrogen cyanide and bisulfite, and tests that distinguish aldehydes from ketones.
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