WAEC Chemistry 2015 Theory — Question 34
Question 34 of 49 from the West African Examinations Council (WAEC) Chemistry 2015 Theory paper, with the correct answer and a full explanation.
Advertisement
4(b). Aluminium can be prepared commercially by the application of electrolysis. (i) Name the electrolyte used in the process; the ore from which the electrolyte is obtained; and the electrodes used in the electrolysis. (ii) Give two reasons why cryolite, Na₃AlF₆, is added to the electrolyte.
Model answer
(i) Electrolyte used: molten alumina (Al₂O₃) dissolved in molten cryolite. Ore: Bauxite. Electrodes: graphite (carbon) is used as both the anode and the cathode. (ii) Cryolite serves as a solvent for the alumina, and it reduces the melting point of the alumina, making the electrolysis more energy-efficient.
Advertisement
Sign up free to unlock
- Score tracking
- Practice history
- Saved questions
- Progress dashboard
- Personalized sessions
- Weak-topic breakdown
…and/or go further with premium services and No Ads.