Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Inorganic Chemistry
869 practice questions
Topics covered
- The Alkali Metals85 practice questions
- The Halogens86 practice questions
- Gases in the Atmosphere86 practice questions
- Reactivity Series163 practice questions
- Extraction and Uses of Metals128 practice questions
- Acids, Alkalis and Titrations83 practice questions
- Acids, Bases and Salt Preparations156 practice questions
- Chemical Tests68 practice questions
Practice questions
261–270 of 374 · Normal
Question 261
3 marks · Normal
Answer and see the solution →During a titration, a student records the following burette readings:
Titration readings Initial reading / cm³ Final reading / cm³ 4.10 21.80 Question 262
3 marks · Normal
Answer and see the solution →Explain why phenolphthalein is a better choice of indicator for an acid–alkali titration than universal indicator. Include two reasons in your answer.
Question 263
4 marks · Normal
Answer and see the solution →Look at the following table of titration results.
Titration results Titration Initial reading / cm³ Final reading / cm³ 1 1.50 23.40 2 2.20 24.10 3 1.70 23.60 (a)[2 marks]Calculate the volume of sodium hydroxide used in each titration.
(b)[1 mark]Suggest which, if any, of the three titrations should be considered an outlier. Give a reason.
(c)[1 mark]State why titrations are repeated.
Question 264
1 mark · Normal
Answer and check →In an acid-alkali titration, which piece of apparatus is used to add the alkali to the acid?
- A.Burette
- B.Measuring cylinder
- C.Pipette
- D.Test tube
Question 265
4 marks · Normal
Answer and see the solution →The steps below are used in a titration experiment to find the volume of sulfuric acid needed to neutralise 25.0 cm³ of potassium hydroxide solution.
(a)[1 mark]State how the potassium hydroxide solution should be measured and transferred to the flask.
(b)[2 marks]Name a suitable indicator for this titration, and state the expected colour change at the endpoint.
(c)[1 mark]Explain why it is important to read the burette at eye level.
Question 266
2 marks · Normal
Answer and see the solution →Describe two key steps you would take to accurately find the volume of sulfuric acid needed to neutralise a fixed amount of sodium hydroxide solution using a titration. Do not include any calculation steps.
Question 267
6 marks · Normal
Answer and see the solution →A student investigates different alkaline solutions and later performs a titration.
(a)[1 mark]State the ion responsible for the alkalinity of sodium carbonate solution.
(b)[2 marks]Write the ionic equation for how carbonate ions in sodium carbonate solution produce this ion, using water.
(c)[1 mark]The student uses sodium carbonate solution in a titration with hydrochloric acid. Name the piece of apparatus they should use to measure 25.0 cm³ of sodium carbonate solution accurately into a conical flask.
(d)[2 marks]State the indicator that should be used for this titration and give the colour change expected at the endpoint.
Question 268
6 marks · Normal
Answer and see the solution →Potassium carbonate is a weak alkali. A student decides to find out how much sulfuric acid is needed to neutralise a sample of potassium carbonate solution.
(a)[1 mark]State one observation that shows potassium carbonate solution is alkaline when tested with a suitable indicator.
(b)[1 mark]Write the name or formula of the ion responsible for the alkaline nature of potassium carbonate solution.
(c)[2 marks]The student prepares for titration by placing 25.0 cm³ of potassium carbonate solution into a conical flask. Describe how to add the acid during the titration and how to recognise when to stop.
(d)[2 marks]Suggest a suitable indicator for this titration and explain why universal indicator is not used.
Question 269
6 marks · Normal
Answer and see the solution →A student titrates 25.0 cm³ of sodium carbonate solution with hydrochloric acid. The burette readings below are recorded.
Burette readings Reading Volume (cm³) Initial 3.10 Final 25.60 (a)[1 mark]Calculate the volume of hydrochloric acid added. Give your answer to two decimal places.
(b)[2 marks]Write a balanced equation for the reaction between sodium carbonate solution and hydrochloric acid.
(c)[3 marks]State the ion produced in sodium carbonate solution that is responsible for its alkaline pH, and explain its formation using an ionic equation.
Question 270
6 marks · Normal
Answer and see the solution →A teacher claims that both sodium hydroxide and sodium carbonate solutions can be used in titrations with hydrochloric acid, but there are important reasons to choose one over the other.
(a)[2 marks]Explain why sodium carbonate solution is considered an alkali, stating the ion responsible for its alkaline nature.
(b)[2 marks]Describe two reasons why, in a titration of hydrochloric acid, sodium hydroxide might be preferred over sodium carbonate.
(c)[2 marks]A student uses phenolphthalein as an indicator for a titration of sodium carbonate with hydrochloric acid. Predict the colour change at the endpoint and what this shows about the pH change.