Why cannot aluminium be obtained by reduction of its oxide with carbon
Question
Why cannot aluminium be obtained by reduction of its oxide with carbon
Solution
Aluminium cannot be obtained by reduction of its oxide with carbon due to the relative positions of aluminium and carbon in the reactivity series.
- The reactivity series is a list of metals arranged in order of their reactivity with other substances.
- Carbon is less reactive than aluminium, meaning it is lower in the reactivity series.
- When aluminium oxide (Al2O3) is heated with carbon, the carbon is not able to displace the aluminium from its oxide.
- This is because aluminium is more reactive than carbon, so it cannot be displaced by carbon in a chemical reaction.
- Instead, a different method called the Hall-Héroult process is used to obtain aluminium.
- In this process, aluminium oxide is dissolved in molten cryolite (Na3AlF6) and then electrolyzed to separate the aluminium metal from the oxygen.
- This process requires a large amount of energy, but it is the most efficient way to obtain pure aluminium.
Similar Questions
Why Al metal cannot be obtained by the reduction of Aluminium oxide with coke?
Aluminium is extracted by theAreduction of its oxide with carbonBelectrolytic decomposition of its molten oxide aloneCelectrolytic decomposition of its molten oxide in cryoliteDreduction of the molten oxide in cryolite using carbon monoxide
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 gain electrons at the anodeMetal ions always gain electrons at the cathodeMetal ions always lose electrons at the anodeMetal ions always lose electrons at the cathode2How is aluminium extracted from the earth?As an aluminium ore known as bauxiteAs pure aluminiumAs an aluminium ore known as cryoliteAs aluminium oxide3In 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 dioxide4Why is molten cryolite mixed with the aluminium oxide prior to electrolysis?To act as a conductor of electricityTo increase the temperature required for the reactionTo hold the electrodes in placeTo lower the temperature required for the reaction5What is the balanced equation for the electrolysis of aluminium oxide?3Al2O3(l) → 6Al(l) + 3O2(g)2Al2O3(l) → 4Al(l) + 3O2(g)Al2O3(l) → Al(l) + O2(g)2Al2O3(l) → 3Al(l) + 4O2(g)
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
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