Describe the use of NPK fertilisers to provide the elements nitrogen, phosphorus and potassium for improved plant growth

Describe tests to identify the anions: (a) carbonate, ( CO_3^{2-} ), by reaction with dilute acid and then testing for carbon dioxide gas (b) chloride, ( Cl^- ), bromide, ( Br^- ), and iodide, ( I^- ), by acidifying with dilute nitric acid then adding aqueous silver nitrate (c) nitrate, ( NO_3^- ), reduction with aluminium foil and aqueous sodium hydroxide and then testing for ammonia gas (d) sulfate, ( SO_4^{2-} ), by acidifying with dilute nitric acid and then adding aqueous barium nitrate (e) sulfite, ( SO_3^{2-} ), by reaction with acidified aqueous potassium manganate(VII)