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CAIE A-Level Chemistry 16.1.4 Identifying CH3CH(OH)– Alcohols

Practise using alkaline iodine to identify a CH3CH(OH)– group from yellow triiodomethane formation.

Syllabus
2028–2030
Course
Chemistry 9701
Level
AS

Exam points

  • identify CH3CH(OH)– in the structure before predicting a positive alkaline-I2 test
  • state the formation of a pale-yellow or yellow CHI3 precipitate and a carboxylate ion
  • count only qualifying alcohol isomers while recognising methyl ketones can also give the iodoform reaction

16.1.4—CH3CH(OH)- alcohol identification question 1

[Maximum number: 1]

Compound V is a liquid.
V contains 77.2 % carbon, 11.4 % hydrogen and 11.4 % oxygen by mass.
V has a relative molecular mass of 280 .

W, X and Y have the same molecular formula, C5H10O\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}.

W, X and Y are added separately to different reagents. Observations for these reactions are described in Table 4.1.

Table 4.1

Table 4.1

State the formula of the yellow precipitate produced when X is added to alkaline I2(aq)\mathrm{I}_{2}(\mathrm{aq}).

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