Question

Complete the following chemical equations.
$A{l_2}{O_3} + 6HCl \to$
$A{l_2}{O_3} + 2NaOH \to$

Answer 1

Hint : Amphoteric oxides are those which can act as acid and base. These oxides can react with both acids and bases producing salt and water. Metals that form amphoteric oxides include Aluminium, Zinc, Lead etc.

Complete Step By Step Answer:
Aluminium forms amphoteric oxide ( $A{l_2}{O_3}$ ) which means aluminium oxide can act as both acid and base. Thus, it can react with both acid and base.
Aluminium oxide ( $A{l_2}{O_3}$ ) reacts with hot dilute hydrochloric acid to give aluminium chloride and water. This shows the basic nature of aluminium oxide.
$A{l_2}{O_3} + 6HCl \to 2AlC{l_3} + 3{H_2}O$
Aluminium oxide ( $A{l_2}{O_3}$ ) reacts with hot, concentrated sodium hydroxide to give sodium aluminate and water. This shows the acidic nature of aluminium oxide.
$A{l_2}{O_3} + 2NaOH \to 2NaAl{O_2} + {H_2}O$
Thus, these reactions predict the amphoteric nature of aluminium oxide. The nature of the reactant decides the acidic or basic nature of aluminium oxide in a chemical reaction. Aluminium oxide is used as a catalyst in many chemical reactions. It is also used in cosmetic products such as blush, lipstick etc. Also, part of the formulation of sunscreen. Aluminium oxide also acts as ceramic oxide and has many applications.

Additional Information:
We have seen that aluminium oxide is an amphoteric oxide. Zinc oxide also acts as amphoteric oxide showing reaction with both acid and base. Zinc oxide ( $ZnO$ ) reacts with Hydrochloric acid to give zinc chloride ( $ZnC{l_2}$ ) and water. It reacts with sodium hydroxide to give sodium zincate ( $N{a_2}Zn{O_2}$ ) and water.

Note :
We completed the given chemical equations by keeping in mind the amphoteric nature of aluminium oxide and then balanced the equation. In such a way that the number of atoms on both sides remains equal.