Specification Point 2.40C (Paper 2C Only):
Describe an experiment to prepare a pure, dry sample of a soluble salt, starting from an Acid and Alkali

Preparation of  Soluble Salts

Using Dilute Acid and Alkali:

Soluble salts prep w acid:alkali, Edexcel IGCSE Chemistry

The heating of the mixture to leave a saturated solution


  • Use pipette to measure alkali into conical flask and add a few drops of indicator (phenolphthalein or methyl orange)
  • Add acid into burette and note the starting volume
  • Add acid in burette into alkali in flask until indicator changes to appropriate colour
  • Note and record the final volume of acid in burette and calculate the volume of acid added (starting volume of acid – final volume of acid)
  • Add this same volume of acid into the same volume of alkali without the indicator
  • Heat to partially evaporate to leave a saturated solution
  • Leave to crystallise
  • Excess solution is decanted and crystals are blot dry

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Author: Jamie

Jamie got a First class degree in Chemistry from Oxford University before going on to teach chemistry full time as a professional tutor. He’s put together these handy revision notes to match the Edexcel IGCSE Chemistry specification so you can learn exactly what you need to know for your exams.