Question 13 of 26intermediate🔧 ApplyShort Answer3 marks

Predict the products formed when cyclohexanecarbaldehyde reacts with following reagents. (i) PhMgBr and then H₃O⁺ (ii) Tollens' reagent (iii) Semicarbazide and weak acid (iv) Excess ethanol and acid (v) Zinc amalgam and dilute hydrochloric acid

(i)
Answer

1-Phenylcyclohexanemethanol (a secondary alcohol)

(ii)
Answer

Cyclohexanecarboxylic acid

(iii)
Answer

Cyclohexanecarbaldehyde semicarbazone

(iv)
Answer

Cyclohexanecarbaldehyde diethyl acetal

(v)
Answer

Methylcyclohexane

Explanation

This question tests the characteristic reactions of aldehydes. (i) Grignard reagents add to aldehydes forming secondary alcohols after hydrolysis. (ii) Tollens' reagent oxidizes aldehydes to carboxylic acids. (iii) Semicarbazide forms semicarbazones with aldehydes. (iv) Aldehydes form acetals with alcohols in acidic medium. (v) Clemmensen reduction converts carbonyl groups to methylene groups.

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