Preparation of Ammonium Fertiliser

Ammonium fertiliser is a type of salt. It can be prepared through a reaction of ammonium hydroxide solution and acid.

 

ammonium hydroxide + acid --> ammonium fertiliser  + water

 

For example, to prepare ammonium sulphate, reactants required are ammonium hdyroxide solution and sulphuric acid.

 

Method used to prepare ammonium sulphate in the laboratory is using titration method.

1. 25 cm³ of ammonium hydroxide 1 mol dm^-3 is pipetted into a conical flask and few drops of phenolphthalein is added.
2. A buret is filled with aulphuric acid. Initial burette reading, V₁ is recorded.
3. Sulphuric acid is added into drops by drops into the ammonium hydroxide solution and the content of the conical flask is swirled.
4. Continue adding sulphuric acid until the colour of phenolphthalein turn to colourless from pink.
5. Final burette readind, V₂ is recorded.
6. Steps 1 - 5 is repeated by adding (V₂- V₁) cm³ of sulphuric acid from the burette into 25 cm³ of ammonium hydroxide solution in the conical flask(with adding phenolphthalein) and the conical flask is swirled.
7. The content of the conical flask is then poured into an evaporating dish and heated until the volume become one third from the initial volume.
8. The content is cooled into room temperature and filtered. The crystal (ammonium salt) is dried by using filter paper.

Diagram to show the set-up of apparatus.