2021 · Q16
Which one of the following metal oxides does not usually react with sodium hydroxide?
general-sciencechemistry
- ACopper oxide
- BAluminium oxide
- CPotassium oxide
- DCalcium oxide
Explanation
Sodium hydroxide is a base, and it reacts with amphoteric oxides but not with basic oxides. Aluminium oxide is amphoteric and reacts with NaOH to form sodium aluminate, so option B does react. Calcium oxide (quicklime) is a basic oxide and does not usually react with sodium hydroxide. Hence calcium oxide is the correct answer.