(a)[2]
Explain why carbon and chlorine are used in water treatment.
(b)[1]
In some regions of the world, drinking water is purified by desalination. What is meant by the term desalination?
(c)[1]
River water can contain agricultural pollutants. These pollutants can lead to eutrophication. Give the names of two anions in fertilisers that contribute to eutrophication.
(d)[2]
An aqueous solution of barium chloride is added to a sample of water that contains sulfate ions. A white precipitate is formed. Construct an ionic equation, including state symbols, for this reaction.