Which one of the following oxides shows both acidic and basic behaviour?

Metal oxides are generally basic in nature, meaning they react with acids to form salt and water [2]. However, certain metal oxides exhibit both acidic and basic characteristics; these are specifically termed amphoteric oxides [1]. According to standard chemical principles, such oxides react with both acids and bases to produce salts and water [1]. Zinc oxide (ZnO) and aluminium oxide (Al2O3) are the primary examples of amphoteric oxides [1]. In contrast, magnesium oxide (MgO) and calcium oxide (CaO) are strictly basic oxides that react with water to form alkaline hydroxides [1]. While copper(II) oxide (CuO) is primarily basic and reacts with acids, it is not classified as a standard amphoteric oxide in the same category as zinc oxide [1]. Therefore, zinc oxide is the correct choice as it demonstrates dual chemical behavior [2].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > Activity 3.9 > p. 41
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 2: Acids, Bases and Salts > Activity 2.7 > p. 22