Paper 2 · Oxides, the pH scale and industrial gases
Which of the following Period 3 oxides is amphoteric, reacting with both acids and bases?
ASilicon dioxide, SiO2, an acidic oxide that reacts only with bases
BSodium oxide, Na2O, a basic oxide that reacts only with acids
CAluminium oxide, Al2O3
DMagnesium oxide, MgO, a basic oxide that reacts only with acids
Explanation: Al2O3 is amphoteric because it reacts with both acids (e.g. HCl) and bases (e.g. NaOH); SiO2 is acidic and Na2O/MgO are basic.
Derived from ZIMSEC Chemistry 5071/2 Paper 2 Theory, November 2013, Q2
