Reactions and tests of aldehydes and ketones (17.8) | Edexcel A-level Chemistry — 9CH0

Students should:
$understand the reactions of carbonyl compounds with: i Fehling’s or Benedict’s solution, Tollens’ reagent and acidified dichromate(VI) ions In equations, the oxidising agent can be represented as [O] ii lithium tetrahydridoaluminate (lithium aluminium hydride) in dry ether In equations, the reducing agent can be represented as [H] iii HCN, in the presence of KCN, as a nucleophilic addition reaction, using curly arrows, relevant lone pairs, dipoles and evidence of optical activity to show the mechanism iv 2,4-dinitrophenylhydrazine (2,4-DNPH), as a qualitative test for the presence of a carbonyl group and to identify a carbonyl compound given data for the melting temperatures of derivatives The equation for this reaction is not required v iodine in the presence of alkali$

understand the reactions of carbonyl compounds with:

i Fehling’s or Benedict’s solution, Tollens’ reagent and acidified dichromate(VI) ions In equations, the oxidising agent can be represented as [O]

ii lithium tetrahydridoaluminate (lithium aluminium hydride) in dry ether In equations, the reducing agent can be represented as [H]

iii HCN, in the presence of KCN, as a nucleophilic addition reaction, using curly arrows, relevant lone pairs, dipoles and evidence of optical activity to show the mechanism

iv 2,4-dinitrophenylhydrazine (2,4-DNPH), as a qualitative test for the presence of a carbonyl group and to identify a carbonyl compound given data for the melting temperatures of derivatives The equation for this reaction is not required

v iodine in the presence of alkali

Reactions and tests of aldehydes and ketones

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Learning Objectives