Question

What are amphoteric oxides? Give two examples of amphoteric oxides.

NCERT Class X
Science - Science

Chapter_Metals and Non Metals

Answer 1

Oxides of metals having both basic and acidic characteristics are called amphoteric oxides. For example, zinc oxide & aluminum oxide.

Explanation:

• These oxides have dual character and can act as both base and acid while undergoing reactions to form salts and water molecules.
• Metals having multiple oxidation states can form amphoteric oxides. Let us look at the example of Aluminium Oxide.
• When it is reacted with an acid such as HCl it takes the characteristics of a base and forms the compound $AlCl_3.$
• While reacting with a base such as NaOH it takes acidic characteristics and forms the compound called $NaAlO_2.$.

Answer 2

Answer: Those metal oxides which react with both acid as well as base in a reaction to give respective salt and water as product are called amphoteric oxides. For example aluminium oxide (Al2O3) and zinc oxide (ZnO)

Al2O3 + 6Hcl -> 2AlCl3 + 3H2O

Al2O3 + 2NaOH -> 2NaAlO2 + H2O

(Sodium Aluminate)