2022 · Q103
Which one of the following oxides reacts with both acid and base?
general-sciencechemistry
- AAluminium oxide
- BCalcium oxide
- CSodium oxide
- DPotassium oxide
Explanation
Aluminium oxide (Al₂O₃) is amphoteric: it reacts with acids to form aluminium salts and with bases to form aluminates. Calcium, sodium and potassium oxides are all basic oxides that react only with acids. This amphoteric character is exploited in the Bayer process to separate alumina from bauxite ore.