St. Anthony’s Canossian Secondary SchoolTest on Electrolysis

NAME: ……………………………( ) CLASS: 4E ……. Date: …………

Section A (10 Marks)

1 What are the products given off at the electrodes during the electrolysis of moltenmagnesium chloride between carbon electrodes?

Anode (positive electrode) Cathode (negative electrode)A Oxygen MagnesiumB Oxygen HydrogenC Magnesium ChlorineD Chlorine Magnesium [ ]

2 Which one of the following correctly describes the processes occurring at the electrodes when molten sodium chloride is electrolysed?

Anode (+) Cathode (-)A Oxidation ReductionB Reduction OxidationC No reaction No reactionD Oxidation Oxidation [ ]

3 Which particles are responsible for the conduction of electricity through (i) metals,electrolytes?

(i) Metals (ii) ElectrolytesA Negative ions Positive ionsB Electrons ElectronsC Positive ions ElectronsD Electrons Positive ions and negative ions [ ]

4 A metal and its chloride have the following properties.

Substance Melting point Boiling point DensityMetal 328°C 1750°C 11.3 g/cm3

Metal chloride 534°C 950°C 4.7 g/cm3

The metal can be obtained by the electrolysis of the molten chloride. In what state will the metal be formed in this electrolysis?A As a solid on the surface of the molten chloride.B As a liquid on the surface of the molten chloride.C As a solid below the molten chloride.D As a liquid below the molten chloride. [ ]

5 Aqueous copper(II) sulfate is electrolysed using copper electrodes. Which one of the following equations represents the reaction taking place at the anode (positive electrode) in this electrolysis?A Cu (s) → Cu2+ (aq) + 2e-

B SO 42− (aq) → SO4 (aq) + 2e-

C Cu2+ (aq) + 2e- → Cu (s)D 4 OH- (aq) → 2H2O (l) + O2 (g) + 4e- [ ]

6 What are the products of the electrolysis of concentrated aqueous sodium chloride using inert electrodes?

Anode (+) Cathode (-)A Chlorine HydrogenB Chlorine OxygenC Chlorine SodiumD Oxygen Chlorine [ ]

7 A constant current was passed through aqueous copper(II) sulfate using copper electrodes. At regular intervals the copper cathode (negative electrode) was removed and weighed. Which one of the following graphs A, B, C or D, represents the mass of the copper cathode plotted against time?

[ ]

8 What particles are present in solid lead(II) bromide and in molten lead(II) bromide?Solid lead(II) bromide Molten lead(II) bromide

A Molecules AtomsB Molecules IonsC Molecules MoleculesD Ions Ions [ ]

9 Concentrated aqueous zinc chloride is electrolysed with platinum electrodes. What are the products at the electrodes?

Anode (+) Cathode (-)A Chlorine ZincB Hydrogen OxygenC Oxygen ZincD Zinc Chlorine [ ]

10 What occurs during the electrolysis of aqueous copper(II) sulfate?A Copper ions move to the negative electrode.B Hydrogen ions move to the positive electrode.C Hydroxide ions move to the negative electrode.D Oxide ions move to the negative electrode. [ ]

Section B (15 marks)

1. Complete the table by naming the products formed when the following liquids are electrolysed using inert electrodes. [5]

Liquid Product formed at Cathode (− ve) Anode (+ ve)

Dilute sulfuric acid (i) OxygenMolten calcium bromide (ii) (iii)Concentrated aqueous sodium chloride (iv) (v)

(i) ........................................... (ii) ............................................................

(iii) ........................................... (iv) ............................................................

(v) ...........................................

2 (a) List all the ions present in a concentrated solution of sodium chloride in water. Give their chemical symbols and names. [4]

.............................................................................................................................................

(b) During an electrolysis, (using inert electrodes) which of these ions travel [2]

(i) to the anode: …………………………………………………………….

(ii) to the cathode? …………………………………………………………

(c) (i) What is produced at the anode? ……………………………… [1]

(ii) What is produced at the cathode? ……………………………… [1]

(d) Write the ionic equation for:(i) c(i) …………………………………………………. [1]

(ii) c(ii) …………………………………………………. [1]

Marking Scheme:

Section A: 10 marks

1 D 2 A 3 D 4 D 5 A6 A 7 A 8 D 9 A 10 A

Section B: 15 marks

1 (i) hydrogen;(ii) calcium;(iii) bromine;(iv) chlorine;(v) hydrogen;

(1 mark each; spelling MUST be correct)

2 (a) sodium ion (Na+), chloride ions (Cl-), hydrogen ions (H+) and hydroxide ions (OH-)(b) (i) chloride ions (Cl-) and hydroxide ions (OH-)

(ii) Sodium ions (Na+) and hydrogen ions (H+)(c) (i) chlorine gas;

(ii) hydrogen gas;(d) (i) 2Cl- Cl2 + 2e;

(ii) 2H+ + 2e H2;