Key Stage 4
Meaning
NPK is a mixture of fertilising compounds used in agriculture.
About NPK
- NPK stands for Nitrogen (N), Phosphorous (P), Potassium (K).
- NPK is generally made by reacting Ammonia with Nitric Acid, reacting Ammonia with Phosphoric Acid and combining these in a mixture with Potassium Chloride which is mined from the ground.
Ammonia + Nitric Acid → Ammonium Nitrate
- <chem>NH3 + HNO3 -> NH4NO3</chem>
Ammonia + Phosphoric Acid → Ammonium Phosphate
- <chem>3NH3 + H3PO4 -> (NH4)3PO4</chem>
- NPK can also include other minerals such as Calcium Phosphate and Calcium Sulphate as plants also need both Calcium and Sulphur.