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Fertilisers and crop yields

Making fertilisers

Most fertilisers are made by the reaction of an acid and an alkali.The table shows some examples.


ammonium nitratenitric acidammonia
ammonium phosphatephosphoric acidammonia
ammonium sulfatesulfuric acidammonia
potassium nitratenitric acidpotassium hydroxide

Making a fertiliser in the lab

The preparation of a fertiliser in a lab involves the following equipment:

  • a measuring cylinder to measure a particular volume of an alkali solution
  • a burette to add acid a little at a time until the alkali has been neutralised
  • a filter funnel to remove solid crystals of fertiliser after evaporating some of the water from the neutral fertiliser solution.

You should be able to predict the name of the acid and the alkali needed to make a given fertiliser. For example, to make ammonium nitrate you should be able to predict that nitric acid and ammonia will be needed. Check the revision bite about neutralisation and naming salts if you are unsure.

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