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
891–900 of 991
Question 891
2 marks · Easy
Answer and see the solution →Describe why the region near the cathode becomes alkaline during the electrolysis of sodium chloride solution.
Question 892
3 marks · Easy
Answer and see the solution →The table shows the tendency to gain electrons (ease of reduction) for some ions in decreasing order.
Reduction Tendency of Some Ions Ion Reduction Tendency K^+ Very difficult Na^+ Very difficult Ca^2+ Difficult H^+ Easier Cu^2+ Very easy A student electrolyses sodium chloride solution. Use the data to answer the following questions.
(a)[1 mark]Suggest which ion, Na⁺ or H⁺, is more easily reduced at the cathode.
(b)[1 mark]Which gas is formed at the cathode?
(c)[1 mark]Explain why sodium metal does not form at the cathode, using the reduction tendency data.
Question 893
1 mark · Easy
Answer and see the solution →What is the symbol equation for the reduction of hydrogen ions at the cathode during electrolysis of sodium chloride solution?
Question 894
3 marks · Easy
Answer and see the solution →During the electrolysis of sodium chloride solution, a student notices the solution near the cathode becomes alkaline.
(a)[1 mark]Name the ion that increases in concentration near the cathode.
(b)[1 mark]Write the half-equation that shows the production of hydrogen gas at the cathode.
(c)[1 mark]Explain why the increase of this ion causes the solution to become alkaline.
Question 895
2 marks · Easy
Answer and see the solution →At the cathode during the electrolysis of sodium chloride solution, two different possible ions could gain electrons. Use the position of sodium and hydrogen in the reactivity series to deduce which ion is discharged.
Question 896
2 marks · Normal
Answer and see the solution →During the electrolysis of sodium chloride solution, hydrogen gas is produced at the cathode rather than sodium metal.
Explain why sodium ions do not gain electrons at the cathode, but hydrogen ions do.
Question 897
4 marks · Normal
Answer and see the solution →In the electrolysis of sodium chloride solution, hydrogen gas forms at the cathode.
(a)[1 mark]State the ions present in sodium chloride solution that move to the cathode.
(b)[2 marks]Write a balanced half-equation to show the reaction occurring at the cathode. (You may use either half-equation involving H+ or H2O.)
(c)[1 mark]Explain, in one sentence, what happens to the electrons at the cathode during this reaction.
Question 898
3 marks · Normal
Answer and see the solution →During the electrolysis of sodium chloride solution, 0.1 mol of hydrogen gas is collected at the cathode.
Calculate the number of moles of hydroxide ions formed around the cathode by the time this hydrogen gas is collected.
Assume the half-equation at the cathode is:
Question 899
3 marks · Normal
Answer and see the solution →After setting up an electrolytic cell with sodium chloride solution, a student predicts sodium metal will be produced at the cathode.
Use your knowledge of reactivity and the process of electrolysis to explain why this prediction is incorrect.
Question 900
4 marks · Normal
Answer and see the solution →The table shows some possible half-equations for reduction at the cathode during the electrolysis of aqueous sodium chloride.
(a)[2 marks]Possible cathode half-equations Equation Product formed at cathode 2Na^+(aq) + 2e^- → 2Na(s) 2H^+(aq) + 2e^- → H2(g) 2H2O(l) + 2e^- → H2(g) + 2OH^-(aq) (b)[2 marks]Identify which equation(s) correctly represent the cathode reaction for the electrolysis of sodium chloride solution and explain your choice.