Nitric acid, HNO3, is used to make fertilisers.

1. (a)Nitric acid is manufactured from ammonia. In the first step, ammonia reacts with oxygen. Balance this equation. NH3 + ______ O2 → ______ NO + ______ H2O[1]
2. (b)(i)Nitric acid is used to make the soluble salt potassium nitrate, KNO3. Name the alkali that reacts with dilute nitric acid to make potassium nitrate.[1]
3. (b)(ii)Describe the experimental procedure used to make colourless aqueous potassium nitrate from the alkali and dilute nitric acid.[2]
4. (b)(iii)Calculate the percentage by mass of nitrogen in potassium nitrate.[2]
5. (c)(i)Fertilisers leach into rivers and cause water pollution problems. Name one other pollutant found in river water.[1]
6. (c)(ii)State three processes used in the purification of river water to produce drinking water.[3]