Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Acids, Bases and Salt Preparations
156 practice questions
Topics covered
- Reactions of acids18 practice questions
- Reacting acids with bases19 practice questions
- Reacting acids with carbonates19 practice questions
- Salt preparations19 practice questions
- Making soluble salts (except sodium, potassium and ammonium salts)19 practice questions
- Making sodium, potassium and ammonium salts18 practice questions
- Making insoluble salts19 practice questions
- Theories of acids and bases19 practice questions
Practice questions
41–50 of 66 · Normal
Question 41
2 marks · Normal
Answer and see the solution →Explain why titration is needed instead of the excess solid method when preparing potassium salts from acid and alkali solutions.
Question 42
4 marks · Normal
Answer and see the solution →A student needs to prepare pure sodium sulfate crystals using a titration of sulfuric acid and sodium hydroxide solutions.
(a)[1 mark]State the first step the student should take before starting the titration.
(b)[1 mark]Describe briefly how the student would use titration to find the correct volume of acid to neutralise the alkali.
(c)[2 marks]After identifying the correct volumes, outline two steps to obtain pure sodium sulfate crystals.
Question 43
3 marks · Normal
Answer and see the solution →Write the balanced chemical equation for the preparation of ammonium sulfate by titrating ammonia solution () with sulfuric acid ().
State the number of moles of ammonia needed to react with one mole of sulfuric acid and identify the formula for ammonium sulfate.
Question 44
3 marks · Normal
Answer and see the solution →Explain the role of methyl orange indicator in an acid–alkali titration to prepare a sodium salt. Why does the indicator colour change at the endpoint, and how does this help determine when the reaction is complete?
Question 45
4 marks · Normal
Answer and see the solution →A student tries to make sodium nitrate by mixing sodium hydroxide and nitric acid using the traditional 'add excess solid, then filter' method. The table shows the solubility of sodium nitrate, sodium sulfate and copper(II) sulfate in water:
Salt Solubility in water at room temperature (g/100g water) Sodium nitrate 92 Sodium sulfate 21 Copper(II) sulfate 23 Use the data to explain why the excess solid method does not work for making sodium nitrate, and how this relates to the need for titration.
Question 46
1 mark · Normal
Answer and check →Which step must be repeated without indicator when preparing pure potassium sulfate crystals by titration?
- A.Mixing the identified volumes of acid and alkali
- B.Adding more indicator to the solution
- C.Heating the reaction mixture directly after titration
- D.Filtering the solution before adding acid
Question 47
2 marks · Normal
Answer and see the solution →Write the balanced chemical equation for preparing sodium chloride from sodium hydroxide and hydrochloric acid. Name the type of reaction that takes place.
Question 48
4 marks · Normal
Answer and see the solution →When using methyl orange during an acid–alkali titration:
(a)[1 mark]State the colour of methyl orange in an alkaline solution.
(b)[2 marks]Describe what you would observe as acid is slowly added to the alkaline solution containing methyl orange.
(c)[1 mark]Explain why methyl orange is suitable for titrations involving strong acids and strong alkalis.
Question 49
2 marks · Normal
Answer and see the solution →Describe how you would make an insoluble salt of calcium sulfate, starting from solutions of calcium nitrate and sodium sulfate.
Question 50
4 marks · Normal
Answer and see the solution →The insoluble salt lead(II) iodide can be made by a precipitation reaction involving lead(II) nitrate and potassium iodide.
(a)[2 marks]Write a balanced chemical equation, with state symbols, for this reaction.
(b)[2 marks]Write an ionic equation, with state symbols, for the formation of lead(II) iodide in this reaction.