Aluminium is extracted by
AHeating bauxite in air at red heat
BCarbon reduction of alumina in a blast furnace
CElectrolysis of fused alumina with cryolite
DBoiling bauxite in dilute sulphuric acid
Answer & Solution
Correct answer: C. Electrolysis of fused alumina with cryolite
1. Aluminium is highly reactive; carbon cannot reduce its oxide.
2. Alumina is dissolved in fused cryolite for electrolysis.
3. Hall-Heroult cell uses carbon electrodes.
4. At the cathode, Al3+ ions accept electrons and pure Al forms.
_Source: Selina Concise Chemistry Class 10, Ch 7 Metallurgy (Mistral OCR'd PDF), section on aluminium extraction_
Related questions
Germanium and silicon used as semiconductors are purified by zone refining becauseNickel is refined by heating the impure metal in a stream of CO to form a volatile carbonyFrom an Ellingham diagram at 1500 K, $\Delta G^\circ$ for $2Fe+O_2\rightarrow 2FeO$ is $-3From an Ellingham diagram, aluminium can reduce which of the following oxides?In an Ellingham diagram the line for the formation of carbon monoxide ($2C + O_2
ightarroAn Ellingham diagram is a plot ofIn the cyanide process, gold is recovered from the leached solution $[Au(CN)_2]^-$ by addiIn the electrolytic refining of copper, the anode and cathode are respectively