(a)[1]
What does the symbol $\rightleftharpoons$ represent?
(b)[1]
Explain why farmers spread fertilisers on the soil where they are going to grow crops.
(c)[1]
Give the name of the compound produced when ammonia reacts with nitric acid.
(d(i))[1]
Explain how calcium oxide helps treat acidic soils.
(d(ii))[1]
Suggest why farmers need to treat soils which are too acidic.