The methanol needed for alternative fuels and solvent production can be manufactured by the catalytic hydrogenation of carbon monoxide. In this process, a mixture of carbon monoxide and hydrogen is passed over a copper-based catalyst. The equation for the reaction is:
CO(g)+2H2(g)⇌CH3OH(g)ΔH=−91 kJ/mol \text{CO}(\text{g}) + 2\text{H}_2(\text{g}) \rightleftharpoons \text{CH}_3\text{OH}(\text{g}) \quad \Delta H = -91 \text{ kJ/mol} CO(g)+2H2(g)⇌CH3OH(g)ΔH=−91 kJ/molIn this part of the question, assume that the reaction reaches a position of equilibrium.
(i) Predict whether a high or low temperature would produce the highest yield of methanol. Give a reason for your choice.
(ii) Predict whether a high or low pressure would produce the highest yield of methanol. Give a reason for your choice.
Explain how a catalyst increases the rate of a reaction.
Some of the methanol produced is oxidised to methanoic acid. In this reaction, methanol vapor is reacted with oxygen. The reaction is reversible and methanol is oxidised to methanoic acid and water.
(i) Write a chemical equation for this reaction.
(ii) Explain why the methanol is oxidised in this reaction.
(iii) The methanoic acid produced can be neutralised by reacting it with sodium carbonate, Na2CO3\text{Na}_2\text{CO}_3Na2CO3. The sodium carbonate reacts with methanoic acid to form sodium methanoate, HCOONa\text{HCOONa}HCOONa, carbon dioxide, and water. Write a chemical equation for this reaction.
28 exam-style questions on Edexcel IGCSE Chemistry Reversible reactions and equilibria. Each one has a worked solution and a mark scheme showing where the marks go.