CAIE A-Level Chemistry AS 17.1.5 The Nature Aldehyde or Ketone of an Unknown Questions

Practise distinguishing aldehydes from ketones in CAIE 9701 using Tollens’ and Fehling’s observations, oxidation behaviour and reduction products.

Exam points

identify an aldehyde from a silver mirror with Tollens’ reagent or brick-red precipitate with Fehling’s
identify a ketone when 2,4-DNPH is positive but Tollens’ and Fehling’s tests remain negative
use reduction product and oxidation behaviour as supporting evidence when several functional groups are possible

[Maximum number: 1]

$4\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCHO}$ is used in the synthesis of some antibiotics.

X, Y and Z are all isomers of $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCHO}$ .

A summary of some of the reactions and properties of X, Y and Z is shown in the table.

Table for Question CAIE A-Level Chemistry AS 17.1.5 The Nature Aldehyde or Ketone of an Unknown Questions question 1 — CAIE A-Level Chemistry AS

Identify the functional group present in Y that causes the recorded observation with Fehling's solution.

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CAIE A-Level Chemistry AS 17.1.5 The Nature Aldehyde or Ketone of an Unknown Questions question 1