- 25 cm3 of ammonium hydroxide 1 mol dm-3 is pipetted into a conical flask and few drops of phenolphthalein is added.
- A buret is filled with aulphuric acid. Initial burette reading, V1 is recorded.
- Sulphuric acid is added into drops by drops into the ammonium hydroxide solution and the content of the conical flask is swirled.
- Continue adding sulphuric acid until the colour of phenolphthalein turn to colourless from pink.
- Final burette readind, V2 is recorded.
- 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.
- 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.
- The content is cooled into room temperature and filtered. The crystal (ammonium salt) is dried by using filter paper.
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.