The ethanol needed for various industrial uses can be made by a process called catalytic hydration of ethene. In this process, a mixture of ethene and steam is passed over a phosphoric acid catalyst. The equation for the reaction is:
C2H4(g)+H2O(g)⇌C2H5OH(g)ΔH=−45 kJ/mol \text{C}_2\text{H}_4(\text{g}) + \text{H}_2\text{O}(\text{g}) \rightleftharpoons \text{C}_2\text{H}_5\text{OH}(\text{g}) \quad \Delta H = -45 \text{ kJ/mol} C2H4(g)+H2O(g)⇌C2H5OH(g)ΔH=−45 kJ/molIn this part of the question, assume that the reaction reaches a position of equilibrium.
Predict whether a high or low temperature would produce the highest yield of ethanol. Give a reason for your choice.
Predict whether a high or low pressure would produce the highest yield of ethanol. Give a reason for your choice.
Explain how a catalyst increases the rate of a reaction.
Some of the ethanol produced is oxidised to ethanoic acid. In this reaction, ethanol vapor is reacted with oxygen. The reaction is reversible and ethanol is oxidised to ethanoic acid and water.
Write a chemical equation for this reaction.
Explain why the ethanol is oxidised in this reaction.
The ethanoic acid produced can be neutralised by reacting it with sodium carbonate, Na2CO3\text{Na}_2\text{CO}_3Na2CO3. The sodium carbonate reacts with ethanoic acid to form sodium ethanoate, CH3COONa\text{CH}_3\text{COONa}CH3COONa, 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.