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CAIE A-Level Chemistry AS 17.1.2 Describe Questions

Practise CAIE 9701 carbonyl reactions by reducing aldehydes and ketones, adding HCN with cyanide catalyst and writing balanced equations.

Syllabus
2028–2030
Course
Chemistry 9701
Level
AS

Exam points

  • reduce aldehydes to primary alcohols and ketones to secondary alcohols with NaBH4 or LiAlH4
  • add HCN with KCN catalyst and heat across C=O to form a hydroxynitrile with one extra carbon
  • write [H] accurately in reduction equations and preserve the carbon skeleton while identifying chiral products

CAIE A-Level Chemistry AS 17.1.2 Describe Questions 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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