SASS Chem Electrolysis AfL

Page 1 ST ANDREW’S SECONDARY SCHOOL NAME CLASS DATE CHEMISTRY (G3) 6092 14.1 Electrolytic Cells ELECTROLYSIS Assessment for Learning 1 Metal M forms the chloride MCl2. M is found between copper and silver in the reactivity series. Which reaction would occur at the anode and at the cathode, of which both are inert, used during the electrolysis of a concentrated aqueous solution of MCl2? Anode Cathode A 2 Cl – ® Cl2 + 2 e – M+ + e – ® M B 2 Cl – ® Cl2 + 2 e – M2+ + 2 e – ® M C 4 OH – ® 2 H2O + O2 + 4 e – M+ + e – ® M D 4 OH – ® 2 H2O + O2 + 4 e – M2+ + 2 e – ® M 2 In which electrolyte would the cathode used increase in mass during electrolysis? A Aqueous copper(II) sulfate B Concentrated aqueous sodium chloride C Concentrated hydrochloric acid D Dilute sulfuric acid 3 Inert electrodes are used in the electrolysis of an aqueous solution containing both CuSO4 and MgSO4. What would be the product formed at the negative electrode? A Copper B Hydrogen C Magnesium D Oxygen 4 What happens when molten barium chloride is electrolysed using inert electrodes? A Ba2+ ions gain electrons at the anode. B Ba2+ ions lose electrons at the cathode. C Cl – ions gain electrons at the anode. D Cl – ions lose electrons at the cathode. 5 What would be observed during the electrolysis of aqueous copper(II) sulfate using carbon electrodes? A A pink-brown solid is deposited at the anode. B Bubbles form at the negative electrode. C The colour of the solution fades. D The negative electrode becomes smaller.

Page 2 6 The diagram shows the electrolysis of concentrated aqueous sodium chloride. What would be the colour of the litmus at each electrode after five minutes? Colour at anode Colour at cathode A Blue Red B Colourless Blue C Red Colourless D Red Blue 7 The electrolysis of a molten compound using inert electrodes would form two atoms of X at the negative electrode and three atoms of Y at the positive electrode. Which row is correct? X is a Y is a Chemical formula of compound A metal non-metal X2Y3 B metal non-metal X3Y2 C non-metal metal X2Y3 D non-metal metal X3Y2 8 The bulb lights with a gas produced at each electrode could be observed during this experiment. What is X? A Aqueous copper(II) sulfate B Concentrated aqueous sodium chloride C Ethanol D Molten lead(II) bromide 5 © UCLES 2012 5070/11/O/N/12 [Turn over 11 Which statement about the particles O2–, F–, Ne, Na+ and Mg2+ is true? They all A contain more electrons than protons. B contain more neutrons than protons. C contain the same number of electrons. D contain the same number of neutrons. 12 T h e Mr of oxygen, O2, is 32 and the Mr of sulfur is 256. What is the formula of a molecule of sulfur? A S2 B S4 C S8 D S16 13 In the experiment shown in the diagram, the bulb lights and a gas is produced at each electrode. bulb +ve –ve X inert electrodes What is X? A a q