What are amphoteric oxides? Give two examples of amphoteric oxides?
OR
Write chemical equations that show aluminium oxide reacts with acid as well as base.

AcademicChemistryNCERTClass 10

When a substance reacts chemically, both as a base or acid is termed as an amphoteric solution. As aluminium oxides, react with both acids and bases, it is known as Amphoteric Oxides.

The Chemical equations are given below:

$( i) \ Al_{2} O_{3} \ +\ 6HCl\ \rightarrow \ 2AlCl_{3} \ +\ 3H_{2} O.$

Aluminium oxide + Acid(HCl) --> Aluminium chloride + water

$( ii) \ Al_{2} O_{3} \ +\ 2NaOH\ \rightarrow \ 2NaAlO_{2} \ +\ H_{2} O.$

Aluminium oxide + Base (NaOH) --> Sodium aluminate  + water.


[Extra information: Amphoteric oxides are oxides of metals that have both acidic as well as basic behaviour. Such metallic oxides react with acids as well as a base to produce salt and water. It can accept or donate the proton or H+ ion, therefore, appearing as an acid or a base. 
 Examples of Amphoteric oxides are aluminum oxide(Al2O3) and zinc oxide(ZnO).
 
In base: $\ ZnO\ +\ 2\ NaOH\ +\ H_{2} O\rightarrow \ Na_{2}[ Zn( OH)_{4}]$
          Zinc Oxide + Sodium Hydroxide--> Sodium Zinc Hydroxide
In acid: $ZnO\ +\ H_{2} SO_{4}\rightarrow \ ZnSO_{4} +\ H_{2} O$
      Zinc Oxide + Sulphuric Acid --> Zinc Sulphate + Water]
raja
Updated on 10-Oct-2022 12:46:54

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