Edexcel A Level Chemistry

Revision Notes

7.3.2 Preparation of Carboxylic Acids

Test Yourself

Preparation of Carboxylic Acids

  • Carboxylic acids are compounds with a -COOH functional group
  • They can be prepared by a series of different reactions

Oxidation of primary alcohols & aldehydes

  • Carboxylic acids can be formed from the oxidation of primary alcohols and aldehydes by either acidified K2Cr2O7 or acidified KMnO4 and reflux
  • The oxidising agents themselves get reduced causing the solutions to change colour
    • In K2Cr2O7 the orange dichromate ions (Cr2O72-) are reduced to green Cr3+ ions
    • In KMnO4  the purple manganate ions (MnO4-) are reduced to colourless Mn2+ ions

 Carboxylic Acids & Derivatives Oxidation of Primary Alcohols and Aldehydes, downloadable AS & A Level Chemistry revision notes

Oxidation of primary alcohols (1) and aldehydes (2) gives carboxylic acids

Hydrolysis of nitriles

  • Carboxylic acids can also be prepared from the hydrolysis of nitriles using either dilute acid or dilute alkali followed by acidification
    • Hydrolysis by dilute acid results in the formation of a carboxylic acid and ammonium salt
    • Hydrolysis by dilute alkali results in the formation of a sodium carboxylate salt and ammonia; Acidification is required to change the carboxylate ion into a carboxylic acid

  • The -CN group at the end of the hydrocarbon chain is converted to a -COOH group

Hydrolysis of nitriles by either dilute acid (1) or dilute alkali and acidification (2) will form a carboxylic acid

You've read 0 of your 0 free revision notes

Get unlimited access

to absolutely everything:

  • Downloadable PDFs
  • Unlimited Revision Notes
  • Topic Questions
  • Past Papers
  • Model Answers
  • Videos (Maths and Science)

Join the 80,663 Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

Philippa

Author: Philippa

Philippa has worked as a GCSE and A level chemistry teacher and tutor for over thirteen years. She studied chemistry and sport science at Loughborough University graduating in 2007 having also completed her PGCE in science. Throughout her time as a teacher she was incharge of a boarding house for five years and coached many teams in a variety of sports. When not producing resources with the chemistry team, Philippa enjoys being active outside with her young family and is a very keen gardener.