Nitrogen molecules, N₂(g), contain two atoms attracted to each other by a triple covalent bond.

1. (a)Describe how the triple covalent bond forms in a N₂(g) molecule. Refer to orbital overlap and hybridisation in your answer.[3]
2. (b)(i)Outline how nitrogen oxides are involved in the formation of photochemical smog.[2]
3. (b)(ii)Construct an equation to demonstrate how a catalytic converter reduces the amount of nitrogen oxide gases released into the atmosphere.[1]
4. (c)N₂(g) is very unreactive. It is difficult to make ammonia, NH₃(g), directly from its elements but it can be made from NH₄Cl(s). Identify a reagent and the conditions required to make NH₃(g) from NH₄Cl(s).[1]
5. (d)(i)Describe what is meant by a strong Brønsted-Lowry acid.[2]
6. (d)(ii)NH₃ is a weak base. Construct an equation that shows the behaviour of NH₃ as a weak Brønsted-Lowry base when dissolved in water.[1]
7. (d)(iii)On Fig. 2.1 sketch a graph to show the change in pH which occurs when HCl(aq) is titrated with NH₃(aq) as described in (d).[2]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.