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JAMB Chemistry 1979 Question 26

Question 26

Metals and their Compounds

In the extraction of aluminium from purified bauxite by electrolysis, cryolite is used because

  1. A.it makes bauxite a better conductor of electricity
  2. B.it makes bauxite melt at a lower temperature
  3. C.it makes aluminium purer
  4. D.it prevents aluminium from getting oxidized
  5. E.it protects the carbon electrodes used in the process.
Show the answer and explanation

Answer: B (it makes bauxite melt at a lower temperature)

Explanation

Pure alumina melts above 2000°C. Dissolving it in molten cryolite lets the electrolysis run at about 950°C, saving a lot of energy.