An agricultural chemist is preparing a highly concentrated liquid blend of NPK fertiliser. They have several chemical compounds available in the laboratory.
Which two of the following compounds each provide exactly two of the three essential macronutrients (nitrogen, N\text{N}N, phosphorus, P\text{P}P, and potassium, K\text{K}K) required for plant growth?
Phosphate rock is insoluble in water and cannot be directly absorbed by crops. To make it useful as a fertiliser, it must be treated with acids to produce soluble phosphorus compounds.
Name the soluble fertiliser product (or mixture of products) obtained when phosphate rock is reacted with:
8 exam-style questions on AQA GCSE Chemistry 10.4 The Haber process and the use of NPK fertilisers, covering 10.4.1 The Haber process and 10.4.2 Production and uses of NPK fertilisers. Each one has a worked solution and a mark scheme showing where the marks go.