CBSE Class 12 Chemistry Notes: The p Block Elements – Fertilizers

FERTILIZERS
For the proper development and natural growth of plants they require adequate supply of essential nutrients. Nitrogen, phosphorus and potassium are regarded as essential plant nutrients and are consumed in large quantities. To overcome the deficiency of these nutrients in soil additional materials containing N, P and K are added to it in the form of manures. Manures are of two types

(i) Natural and
(ii) Artificial
Artificial fertilizers are the chemical substances which are added to the soil as to make up the deficiency of essential elements are called fertilizers.

Nitrogenous fertilizers
The important nitrogenous compounds used as fertilizers are :

(v) Urea, NH₂CONH₂

Preparation
CO₂ + 2NH₃ → NH₂COONH₄ (Ammonium carbonate)
NH₂COONH₄ → NH₂CONH₂ + H₂O
Out of all, urea is having highest nitrogen content (46.6%). It does not even alter the pH of soil. It can be used for all type of crops.

Phosphatic fertilizers

NPK fertilizers
Fertilizers containing N, P and K in suitable adjusted proportions are known as NPK fertilizers. These are obtained by mixing nitrogenous, phosphatic and potash fertilizers in suitable proportion.

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