CIE AS Chemistry (9701) exams from 2022

Revision Notes

3.5.2 Reactions of Aldehydes & Ketones

Reactions of Aldehydes & Ketones

Reduction of aldehyde & ketones

  • Aldehydes and ketones can be reduced by reducing agents such as NaBH4 or LiAlH4
  • Aldehydes are reduced to primary alcohols
  • Ketones are reduced to secondary alcohols


Hydroxy Compounds Reduction, downloadable AS & A Level Chemistry revision notes

Reduction of aldehydes and ketones to form primary and secondary alcohols

Nucleophilic addition with HCN

  • Aldehydes and ketones can undergo nucleophilic addition with hydrogen cyanide, HCN
  • The cyanide ion, CN, acts as a nucleophile and adds across the C-O bond
  • Aldehydes and ketones react with HCN, KCN as catalyst and heat to produce hydroxynitriles
    • Hydroxynitriles are nitriles containing a hydroxy, -OH, group


Carbonyl Compounds Nucleophilic Addition, downloadable AS & A Level Chemistry revision notes

Nucleophilic addition to ethanal (aldehyde) and propanone (ketone)

Exam Tip

The nucleophilic addition of HCN to an aldehyde or ketone increases the length of the carbon chain by one carbon atom!

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Fran has taught A level Chemistry in the UK for over 10 years. As head of science, she used her passion for education to drive improvement for staff and students, supporting them to achieve their full potential. Fran has also co-written science textbooks and worked as an examiner for UK exam boards.

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