Explain how oxides of nitrogen form in car engines and describe their removal by catalytic converters, e.g. (2CO + 2NO ightarrow 2CO_2 + N_2)

Describe the reactions, if any, of: (a) potassium, sodium and calcium with cold water (b) magnesium with steam (c) magnesium, zinc, iron, copper, silver and gold with dilute hydrochloric acid and explain these reactions in terms of the position of the metals in the reactivity series

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