Question

“ The $BeO$ and $A{l_2}{O_3}$ are amphoteric.”
Answer whether the above statement is true or false.

Answer 1

Hint : An amphoteric oxide is an oxide which can act as either an acid or base in a reaction to give product as salt and water. Amphoterism of oxides depends on the oxidation states of chemical species. Metals have multiple oxidation states so they easily form amphoteric oxides and hydroxides.

Complete Step By Step Answer:
$BeO$ and $A{l_2}{O_3}$ both metallic oxides are amphoteric oxides as they both can act as either an acid or base in reaction so that they produce salt and water.
In case of aluminium oxide:
The reaction of $A{l_2}{O_3}$ with acid is given as:
$A{l_2}{O_3} + HCl \to AlC{l_3}$
And the reaction of $A{l_2}{O_3}$ with base is given as:
$A{l_2}{O_3} + NaOH \to NaAl{O_2}$
So it is clear that it gives salt when reacting with acid as well as base which means it behaves as base in the reaction with acid and on the other hand it behaves as acid in the reaction with base.
That means it is an amphoteric oxide.
In case of beryllium oxide:
The reaction of $BeO$ with acid is given as:
$BeO + 2HCl + {H_2}O \to BeC{l_2} + 2{H_2}O$
And the reaction of $BeO$ with base is given as:
$BeO + 2NaOH + {H_2}O \to N{a_2}Be{(OH)_4}$
So it is clear that it gives salt when reacting with acid as well as base which means it behaves as base in the reaction with acid and on the other hand it behaves as acid in the reaction with base.
That means it also is an amphoteric oxide.
In simple words, they both can react with acid as well as base to give salt and water. $BeO$ and $A{l_2}{O_3}$ are amphoteric oxides also because of diagonal relationship. As oxides of aluminium are amphoteric so oxides of beryllium are also amphoteric, that is $BeO$ is also an amphoteric oxide.
So, the above statement is correct.

Note :
There are some other elements that formed amphoteric oxides are gallium, indium, vanadium, zirconium, chromium, scandium, titanium, cobalt, iron, copper, silver, germanium, gold, tellurium, antimony and bismuth.