Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
The electrolysis of molten compounds
19 practice questions
Practice questions
1–10 of 19
Question 1
1 mark · Easy
Answer and see the solution →State the product formed at the cathode during the electrolysis of molten calcium chloride ().
Question 2
3 marks · Easy
Answer and see the solution →The diagram shows the apparatus used to electrolyse molten lithium iodide ().
Electrolysis apparatus for molten LiI Answer the following questions about this electrolysis.
(a)[1 mark]Name the ion in molten that is attracted to the cathode.
(b)[1 mark]State what is formed at the anode.
(c)[1 mark]Write the half-equation for the reaction at the cathode.
Question 3
2 marks · Easy
Answer and see the solution →Write the balanced half-equation for the reaction at the anode during the electrolysis of molten potassium bromide (), and state how many electrons are involved per bromine molecule formed.
Question 4
3 marks · Easy
Answer and see the solution →The table below shows the ions present in three molten ionic compounds:
Compound Ions present A: MgF_2 B: KCl C: CaBr_2 (a)[1 mark]For compound B, name the product formed at the anode.
(b)[1 mark]For compound C, write the half-equation for the reaction at the cathode.
(c)[1 mark]For compound A, state the formula of the ion that gains electrons at the cathode.
Question 5
1 mark · Easy
Answer and see the solution →Write the formula of the ion that is reduced at the cathode when molten barium chloride () is electrolysed.
Question 6
3 marks · Easy
Answer and see the solution →Molten tin(II) chloride () is electrolysed using inert electrodes.
(a)[1 mark]Name the element formed at the cathode.
(b)[1 mark]Write the half-equation for the reaction at the anode.
(c)[1 mark]Explain briefly what happens to the ions during electrolysis.
Question 7
2 marks · Easy
Answer and see the solution →During the electrolysis of molten sodium bromide (), write the half-equation for the reaction at the cathode. State the number of electrons gained by each sodium ion.
Question 8
2 marks · Easy
Answer and see the solution →Molten calcium iodide () is electrolysed using inert electrodes.
(a)[1 mark]Write the half-equation for the reaction that occurs at the cathode during the electrolysis of molten calcium iodide.
(b)[1 mark]Explain why iodide ions move to the anode in this process.
Question 9
2 marks · Normal
Answer and see the solution →State the products formed at the electrodes when molten sodium chloride is electrolysed. For each product, name the electrode where it forms.
Question 10
4 marks · Normal
Answer and see the solution →Aluminium oxide can be electrolysed when molten.
(a)[1 mark]State the names and formulas of the ions present in molten aluminium oxide.
(b)[1 mark]Write the half-equation for the reaction at the cathode.
(c)[1 mark]Write the half-equation for the reaction at the anode.
(d)[1 mark]Identify the product formed at each electrode.