What is the full form of chemical fertiliser, N.P.K.?
A) Nitrogen, Phosphorus and Calcium
B) Nitric Acid, Phosphorus and Calcium
C) Nitrogen, Phosphorus and Potassium
D) Nitric Acid, Phosphorus and Potassium

Think of the three primary plant macronutrients taught in Class 8 Science. Their chemical symbols are N, P, and K—with K coming from the Latin name kalium.

Complete Answer
In chemical fertilisers, N.P.K. stands for Nitrogen (N), Phosphorus (P), and Potassium (K). These are the core macronutrients required in the largest amounts by crops. Nitrogen supports leafy/vegetative growth and chlorophyll formation; Phosphorus aids root development, flowering, seed formation and energy transfer (ATP); Potassium regulates water balance, enzyme activation, disease tolerance and overall plant hardiness. Commercial NPK fertilisers are sold in graded ratios—e.g., 10-26-26, 17-17-17, 20-20-0—to match crop and soil needs. Balanced use (preferably soil-test based) improves yield while reducing nutrient losses and environmental risks.

The correct option is (C) Nitrogen, Phosphorus and Potassium

Additional Information

• Sources: N commonly from urea/ammonium compounds, P from DAP/SSP, K from MOP (muriate of potash).
• Deficiency cues (quick): N → overall yellowing (older leaves first); P → stunted growth, poor rooting; K → scorched leaf margins, weak stems.
• Best practices: Split N applications, mix chemical fertilisers with FYM/compost (INM), and follow soil health card or agronomy guidance to avoid runoff and eutrophication.

The letters in N.P.K. refer to elements, not acids or salts—so it’s not “Nitric Acid–Phosphorus–Potassium,” and Calcium (Ca) is not part of NPK. The K is for Potassium because of its Latin name kalium.