Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Principles of Chemistry
991 practice questions
Topics covered
- States of Matter102 practice questions
- Elements, Compounds and Mixtures69 practice questions
- Atomic Structure108 practice questions
- The Periodic Table103 practice questions
- Chemical Formulae, Equations and Calculations Part 119 practice questions
- Chemical Formulae, Equations and Calculations Part 2144 practice questions
- Ionic Bonding143 practice questions
- Covalent Bonding68 practice questions
- Metallic Bonding19 practice questions
- Electrolysis198 practice questions
Practice questions
901–910 of 991
Question 901
1 mark · Normal
Answer and see the solution →During the electrolysis of sodium chloride solution, why does the solution near the cathode become alkaline?
- A.Hydrogen gas dissolves to form alkali.
- B.Sodium ions react with water to make sodium hydroxide.
- C.Hydroxide ions are produced at the cathode.
- D.Chlorine neutralises acid at the cathode.
Question 902
2 marks · Normal
Answer and see the solution →State two reasons why hydrogen is produced at the cathode, and not sodium, in the electrolysis of sodium chloride solution.
Question 903
4 marks · Normal
Answer and see the solution →Here are two possible half-equations for a reaction occurring at the cathode during electrolysis of sodium chloride solution:
(a)[1 mark]Name all ions present in the solution that could be reduced at the cathode.
(b)[2 marks]Which of the two half-equations shows the production of hydrogen gas from water? Explain your answer.
(c)[1 mark]Write a word equation for the cathode reaction using water as the starting material.
Question 904
2 marks · Hard
Answer and see the solution →Write a balanced half-equation, including state symbols, for the reduction that takes place at the cathode during the electrolysis of sodium chloride solution. State the physical state of each species involved.
Question 905
5 marks · Hard
Answer and see the solution →A student sets up an electrolytic cell using sodium chloride solution and collects the gases produced. They notice that the solution near the cathode becomes increasingly alkaline as the reaction proceeds.
(a)[1 mark]Name the ion that increases in concentration around the cathode.
(b)[2 marks]Write a balanced chemical equation, with state symbols, for the process at the cathode that explains this change.
(c)[2 marks]Explain why the solution near the cathode becomes alkaline as electrolysis continues. Relate your answer to the ions produced and removed at the electrode.
Question 906
2 marks · Hard
Answer and see the solution →Explain why sodium ions are not discharged at the cathode during the electrolysis of sodium chloride solution, whereas hydrogen is.
Question 907
1 mark · Easy
Answer and see the solution →State the product formed at the cathode during the electrolysis of copper(II) sulfate solution using inert electrodes.
Question 908
2 marks · Easy
Answer and see the solution →The reactivity series places copper below hydrogen. Using this fact and your knowledge of ions in copper(II) sulfate solution, explain why copper is deposited at the cathode and not hydrogen during electrolysis with inert electrodes.
Question 909
2 marks · Easy
Answer and see the solution →Describe how a sample of copper(II) sulfate solution would be different after it is electrolysed for a long time using inert electrodes.
Question 910
3 marks · Easy
Answer and see the solution →The table below shows the ions present in copper(II) sulfate solution before and after electrolysis with inert electrodes.
Ion Before electrolysis After prolonged electrolysis Cu^{2+} Present Absent SO_4^{2-} Present Present H^+ Present Present OH^- Present Absent From the table, state which ion is responsible for the product formed at the cathode, and name the product.
From the table, state which ion is responsible for the product formed at the anode, and name the product.
Using your answers, give the overall effect of electrolysis on the copper(II) sulfate solution.