EXERCISES
1. What metals and compounds studied are prepared by electrolysis?
2. Write the equation for the reaction between aluminium and hydrochloric acid; between aluminium and sulphuric acid (in two steps).
3. What hydroxides other than aluminium hydroxide have both acid and basic properties?
4. Write equations showing the methods used for preparing aluminium hydroxide and sulphate.
5. Write the general formula of an alum, representing an atom of an alkali metal by X and an atom of a trivalent metal by Y.
6. What is meant by the term polysilicic acid, as used in the discussion of aluminium silicates?
7. Compare the properties of the hydroxides of the different groups of metals so far studied.
8. In what respects does aluminium oxide differ from calcium oxide in properties?
9. Supposing bauxite to be 90% aluminium hydroxide, what weight of it is necessary for the preparation of 100 kg. of aluminium?