Uses of Ammonia

Uses of Ammonia:

 

The production of ammonia is done on large scale and large quantities are produced because it has many important uses.

 

Manufacture of Fertilizers:

The main use of ammonia is in the manufacture of fertilizers. Approximately 75% of all ammonia produced is converted into various ammonium compounds like ammonium sulphate (NH₄)₂SO₄, ammonium nitrate NH₄NO₃, and urea NH₂CONH₂. These compounds are called nitrogenous fertilizers. They are solids for easy handling, and water soluble so that they seep into the soil to be absorbed by the roots of the plant. These fertilizers provide nitrogen to the plant, which is an important element for healthy plant growth, as it helps in making the proteins which are needed for healthy growth of stems and leaves.

There are other important elements for healthy plant growth, too, such as phosphorus, which is necessary for good root growth, and potassium, which is important in the development of flowers and food. These important elements come from other sorts of fertilizers. If a fertilizer contains only one of the important elements, it is called a straight fertilizer. If these fertilizers are mixtures of the important elements, they are called compound fertilizers.

Beside these elements, there are also trace elements needed for the healthy growth of a plant, for example calcium, magnesium, sodium, sulphur, and tiny amounts of copper, zinc, boron, manganese and iron.

But what you basically must keep in mind in this chapter is that how ammonia is used to manufacture fertilizers. These are artificial fertilizers. The nitrogen content of such a fertilizer can be calculated by percentage composition.

The use of artificial fertilizers, however, has its disadvantages. Large scale use of these causes a pollution problem eutrophication: the high solubility of the fertilizer allows it to be leached from the soil and washed into streams, and when it finally settles in still water, it causes algae to grow and removes oxygen from the water.

 

Manufacture of Nitric Acid:

Nitric acid is made by the catalytic oxidation of ammonia over heated platinum. Oxidising ammonia produces oxides of nitrogen which can then be dissolved in water to produce nitric acid.

Most of the nitric acid made is used to make the all-important fertilizers. Other uses of nitric acid include making explosives and making dyes.

 

Use as a Solvent:

Aqueous ammonia is used as a degreasing agent, as it is a good solvent of grease and fat.

 

Let us go through some questions now, so that we can get a clearer idea of the whole chapter.

 

Q1. Which of these compounds does not always contain nitrogen?

1. Protein
2. Fertilizer
3. Nitrate
4. Nitrite

 

The answer to that question, as most of you might have already deduced, is B, Fertilizers. I mentioned this fact earlier in my lecture that fertilizers are generally made up of ammonia, potassium, or phosphorus, not necessarily ammonia.

 

Now solve this question yourself.

 

Q2. Which of the following reactants will not produce ammonia on heating?

1. Ammonium chloride and potassium hydroxide
2. Ammonium sulphate and calcium oxide
3. Potassium hydroxide and sodium nitrate
4. Sodium hydroxide and ammonium nitrate