Question

Anirudh took two metal oxides: aluminium oxide and magnesium oxide, as shown in the pictures given below. But he forgot to label them. How will you guide/help Anirudh to identify the oxides and label them?

 

Answer 1

Aqueous solution of magnesium oxide turns red litmus to blue. Aluminium oxide is amphoteric and insoluble in water. Thus, it does not change the colour of either blue or red litmus.

Answer 2

Magnesium oxide reacts with acid only, whereas aluminium oxide reacts with acids and bases, which are amphoteric.