BRAINCAKEpH of Period 3 Oxide Solutions
The pH of the solution formed when each Period 3 oxide is added to water:
• Na2O: pH 14 (strongly alkaline)
• MgO: pH about 9 to 10 (weakly alkaline)
• Al2O3 and SiO2: pH 7 (insoluble, so the water is unchanged)
• P4O10: pH about 0 to 1
• SO2: pH about 2 to 3
• SO3: pH about 0 to 1
Why the metal oxides give alkaline solutions. Ionic oxides contain the oxide ion, a strong base, which takes a proton from water:
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Key terms in this lesson
- ionic product of water
- The equilibrium constant for the ionisation of water, Kw = [H+][OH-], equal to 1.0 x 10-14 mol2 dm-6 at 25 degrees C.
More in Period 3 Elements and Oxides
- Reactions of Sodium and Magnesium with Water
- Reactions of Period 3 Elements with Oxygen
- Period 3 Oxides
- Melting Points of Period 3 Oxides
- Reactions of Period 3 Oxides with Water
- Acid-Base Character of Period 3 Oxides
- Amphoteric Aluminium Oxide
- Equations for Period 3 Oxides with Acids and Bases
All 10 lessons in Period 3 Elements and Oxides · All AQA A-level Chemistry topics