iGCSE Chemistry 0620 Extended - 10.2 Fertilisers- Exam Style Questions Paper 2- New Syllabus
▶️ Answer/Explanation
To supply all three NPK elements, we need a mixture containing nitrogen (N), phosphorus (P), and potassium (K). Option A has ammonium phosphate (providing N and P) and potassium chloride (providing K). Option B lacks potassium. Option C lacks potassium. Option D has nitrogen and potassium from ammonium nitrate and potassium chloride, but contains no phosphorus at all. Therefore, only Option A provides all three elements.
✅ Answer: (A)
✅ Answer: (A)
▶️ Answer/Explanation
Ammonium sulfate is made by reacting ammonia with sulfuric acid. The ammonia (gap 1) is produced by the Haber process (gap 2), which involves reacting nitrogen and hydrogen at 450 °C and 200 atm using an iron catalyst (gap 3). The Haber process equation is N₂(g) + 3H₂(g) ⇌ 2NH₃(g). This matches option C: ammonia / Haber / iron.
✅ Answer: (C)
✅ Answer: (C)
▶️ Answer/Explanation
The three essential elements for improved plant growth in NPK fertilisers are nitrogen (N), phosphorus (P) and potassium (K). Option B provides N from \((NH_4)_2HPO_4\), P from the same compound, and K from \(K_2SO_4\). The other options lack at least one of these three elements (e.g., option A has N and K but no P; option C has N and P but no K; option D has N and K but no P).
✅ Answer: (B)
✅ Answer: (B)