1. Which pair of compounds could be used in the preparation of calcium sulfate?

2. The compounds Na₂O, Al₂O₃ and SO₂ respectively are

3. Which compound is an amphoteric oxide?

4. The following statements about dilute sulphuric acid are all correct.

            1. A white precipitate is formed when aqueous barium chloride is added.

            2. The solution turns anhydrous copper (II) sulphate from white to blue.

            3. Addition of Universal Indicator shows that the solution has a pH value of less than 7.0.

            4. The solution reacts with copper (II) oxide, forming a blue solution.

            Which two statements confirm the acidic nature of the solution?

5. Which element will burn in oxygen to form an acidic oxide?

6. Which compound is an amphoteric oxide?

7. A colourless liquid in an unlabelled bottle is tested as shown.

            • Litmus paper turns red.

            • Magnesium ribbon fizzed.

            • Reaction with aqueous barium nitrate produced a white precipitate.

            What is the colourless liquid?

8. Aqueous ammonia is added to a solution of a metal sulphate.

            A green precipitate that is insoluble in excess of the aqueous ammonia forms.

            Which metal ion is present?

9. In which industrial process is water essential?

10. Aluminium chloride dissolves in water to form a solution with a pH less than 7.

            Which ion in the solution makes the solution have a pH less than 7?