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This question is about sulfuric acid and sulfates - AQA - GCSE Chemistry - Question 5 - 2017 - Paper 3
Question 5
This question is about sulfuric acid and sulfates. One reaction in the industrial production of sulfuric acid is: 2SO₂ (g) + O₂ (g) ⇌ 2SO₃ (g) The forward reactio... show full transcript
Worked Solution & Example Answer:This question is about sulfuric acid and sulfates - AQA - GCSE Chemistry - Question 5 - 2017 - Paper 3
Step 1
Explain why a moderately high temperature, instead of a low temperature, is used for this reaction.
Answer
A moderately high temperature is used in this reaction because it increases the rate of reaction. Although lower temperatures would favor the formation of SO₃ due to the exothermic nature of the forward reaction, the yield would be decreased. Therefore, a compromise temperature is employed to balance the reaction rate and yield.
Step 2
Explain why you would expect this reaction to be carried out at high pressure.
Answer
This reaction is expected to be carried out at high pressure because increasing the pressure shifts the equilibrium to the right, favoring the production of SO₃. This is due to the fact that there are more moles of gas on the left side of the equation than on the right, thereby resulting in a greater volume of gas.
Step 3
Step 4
Describe how sodium hydroxide solution is used to distinguish between a solution of magnesium sulfate and a solution of aluminium sulfate.
Answer
When sodium hydroxide solution is added to a solution of aluminium sulfate, a white precipitate is formed, which dissolves in excess sodium hydroxide. In contrast, when added to magnesium sulfate, a white precipitate is formed that does not dissolve in excess sodium hydroxide. This difference in solubility allows for the distinction between the two sulfate solutions.