In the electrolysis of aluminium oxide, the electrodes are made of carbon in the form of graphite. Which of the following statements is not true?The presence of carbon electrodes reduces the amount of energy required for the electrolysis reactionGraphite is used as an electrode because it is a good conductor of electricityCarbon is relatively unreactive, and the electrodes do not therefore react with the aluminium oxide during electrolysisAt extremely high temperatures, the oxygen produced during electrolysis reacts with the carbon anode to form carbon dioxide

Which of the following statements is true?Metal ions always lose electrons at the cathodeMetal ions always lose electrons at the anodeMetal ions always gain electrons at the cathodeMetal ions always gain electrons at the anode2How is aluminium extracted from the earth?As an aluminium ore known as cryoliteAs an aluminium ore known as bauxiteAs aluminium oxideAs pure aluminium3In the electrolysis of aluminium oxide, the electrodes are made of carbon in the form of graphite. Which of the following statements is not true?The presence of carbon electrodes reduces the amount of energy required for the electrolysis reactionAt extremely high temperatures, the oxygen produced during electrolysis reacts with the carbon anode to form carbon dioxideGraphite is used as an electrode because it is a good conductor of electricityCarbon is relatively unreactive, and the electrodes do not therefore react with the aluminium oxide during electrolysis4Why is molten cryolite mixed with the aluminium oxide prior to electrolysis?To increase the temperature required for the reactionTo hold the electrodes in placeTo act as a conductor of electricityTo lower the temperature required for the reaction5What is the balanced equation for the electrolysis of aluminium oxide?2Al2O3(l) → 3Al(l) + 4O2(g)Al2O3(l) → Al(l) + O2(g)2Al2O3(l) → 4Al(l) + 3O2(g)3Al2O3(l) → 6Al(l) + 3O2(g)

Why cannot aluminium be obtained by reduction of its oxide with carbon

Which of the following statements about ‘inert’ electrodes is not true?They can be made of carbonAt the cathode, positive ions gain electrons to become metal elementsAt the anode, negative ions lose electrons and become non-metal elementsThey take part in the electrolysis reactions2Copper can be purified by electrolysis using metal (non-inert) electrodes. Which of the following correctly describes how the electrolysis cell should be set up?Cathode should be impure copper, anode should be pure copperCathode should be pure copper, anode should be carbonCathode should be carbon, anode should be impure copperCathode should be pure copper, anode should be impure copper3What happens at the anode?Sulfate ions formImpurities from the impure copper are collectedCopper ions formCopper atoms form4What happens at the cathode?Sulfate ions formImpurities from the impure copper are collectedCopper ions formCopper atoms form5The core practical investigates the changes in electrode mass during the electrolysis of copper sulfate solution at different currents. Which of the following would you not expect to happen?The gain in mass by the cathode is the same as the loss in mass by the anodeThe cathode increases in massThe anode decreases in massThe higher the current the lower the change in mass between the anode and cathode6Sometimes the mass gain at the cathode may be slightly lower than the mass loss at the anode. What is an explanation for this?All of theseIf the anode is not pure copper, any impurities will be deposited in the electrolyte rather than at the cathodeSome of the propanone used in the washing process may not have evaporated properly from the anodeSome of the copper deposited at the cathode may have fallen off during the washing process

Why does the positive anode need regular replacement in extraction of Aluminium from Al2O3?1 markAnode gains weightAnode dissolves in electrolyteAnode reacts with carbon to form carbon dioxideAnode becomes resistant to electricity

Metals less reactive than carbon can be extracted using...A:ElectrolysisB:Displacement with a more reactive metalC:No extraction needed they are found as native metalsD:Reduction with carbon