Write only equation of propanone for aldol condensation.

Propanone reacts with dilute barium hydroxide to form β -hydroxy ketone (ketol), which on dehydration gives α , β -unsaturated ketone ( 4 -Methylpent- 3 -en- 2 -one). The reaction is as shown below: 2 CH 3 COCH 3 → Ba OH 3 CH 3 2 C OH CH 2 COCH 3 → ∆ CH 3 2 C = CHCOCH 3 + H 2 O

Write only equation of propanone for Wolff-Kishner reduction.

Propanone can be reduced to propane by treating with hydrazine followed by heating with sodium hydroxide in ethylene glycol at 200 ∘ C . This reaction is called Wolff-Kishner reduction.The equation is as given below: CH 3 COCH 3 + NH 2 - NH 2 → - H 2 O CH 3 2 C = N - NH 2 → ∆ NaOH / glycol CH 3 CH 2 CH 3 + N 2

Explain : (a) Clemmensen's reduction of aldehydes and ketones. (b) Tollen's test of aldehydes.

a) The reduction of carbonyl group ( > C = O ) of aldehydes and ketones with zinc amalgam ( Zn / Hg alloy) in concentrated hydrochloric acid to - CH 2 group to form hydrocarbon, is called Clemmensen reduction. RCOR ′ → HCl Zn − Hg RCH 2 R ′ b) In Tollens’ test for aldehydes, Tollens’ reagent is used, which is a freshly prepared ammoniacal silver nitrate solution containing [ Ag ( NH 3 ) 2 ] + . It is a mild oxidising agent and therefore, aldehydes are readily oxidised whereas ketones are not. It is thus, used as a qualitative laboratory test to distinguish between an aldehyde and a ketone. CH 3 CHO + 2 Ag NH 3 2 + + 3 OH − → CH 3 COOH + 2 Ag + 2 H 2 O + 4 NH 3

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter -1 - Aldehydes, Ketones and Carboxylic Acids>Gujarat Board-2019>Q 9

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By hydrolysis of which substance carboxylic acid can be obtained?

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