Ammonium sulfate and ammonium nitrate are two common compounds used as fertilisers. They are both easy to make in the lab by carrying out a simple neutralisation reaction. The diagram below outlines how to make ammonium sulfate by carrying out a simple neutralisation reaction:

Making ammonium sulfate by neutralisation using ammonium hydroxide solution

• step 1. - to make a salt called a sulfate you must use sulfuric acid.
• step 2.- a few drops of methyl orange indicator are added to the acid. Methyl orange indicator is red in acid and yellow in neutral/alkaline solutions.
• To neutralise the acid slowly add; with constant stirring the alkaline ammonium hydroxide solution. The acid will have been neutralised when the indicator jus turns yellow.
• step 4. - The indicator; in this case methyl orange is a coloured dye and must be removed otherwise the final crystals of ammonium sulfate will be covered in the coloured indicator. Charcoal is good at removing smells, stains and odours. So simply add a few spatulas full of powdered charcoal and stir for a few minutes.
• step 5 - The charcoal needs to be removed from the solution now. This is easily done by filtration.
• step 6 - Heat the salt solution over a water bath until approximately 75% of the solution has evaporated.
• step 7 - Place the remaining salt solution on an evaporating basin and leave in a warm sunny spot to allow the remaining water to evaporate and the ammonium sulfate crystals to grow.

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