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CAIE A-Level Chemistry 17.1.2 Reactions of Aldehydes and Ketones

Practise reducing carbonyl compounds to alcohols and adding HCN to form hydroxynitriles under catalytic conditions.

Syllabus
2028–2030
Course
Chemistry 9701
Level
AS

Exam points

  • reduce an aldehyde to a primary alcohol or ketone to a secondary alcohol using NaBH4 or LiAlH4
  • add HCN with KCN catalyst and heat across C=O to form a hydroxynitrile with one extra carbon
  • use [H] accurately in a balanced reduction equation and preserve the original carbon skeleton

17.1.2—Describe question 1

[Maximum number: 2]

4(CH3)3CCHO4\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCHO} is used in the synthesis of some antibiotics.

Question (a)

(a)

Two reaction sequences are shown.

Figure for Question (a) — CAIE A-Level Chemistry AS
Figure for Question (a) — CAIE A-Level Chemistry AS
[ 1 ]

Question (i)

(i)

Give the balanced equation for the reaction of (CH3)3CCHO\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCHO} with NaBH4\mathrm{NaBH}_{4} to form S.

Use [H] to represent an atom of hydrogen provided by NaBH4\mathrm{NaBH}_{4}.

[ 1 ]

Question (b)

(b)

X, Y and Z are all isomers of (CH3)3CCHO\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 (b) — CAIE A-Level Chemistry AS
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Question (i)

(i)

State the role of NaCN in the reaction in (c)(vii).

[ 1 ]
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