Question

Scandium oxide is insoluble in water. Describe how you could show that it is an amphoteric oxide.

Answer 1

Hint: In scandium oxide, there are two atoms of scandium and three atoms of oxygen. So, the formula of scandium oxide is $S{{c}_{2}}{{O}_{3}}$. If it can react with acid as well as a base then the compound is said to be amphoteric.

Complete answer:
Scandium is an element of d-block and group 3. Since it is an element of d-block, it is a transition metal. In scandium oxide, there are two atoms of scandium and three atoms of oxygen. So, the formula of scandium oxide is $S{{c}_{2}}{{O}_{3}}$. The oxidation of scandium in scandium oxide is +3, so it is also written as scandium (III) oxide. The oxide of scandium is not soluble in water but it can be soluble in hot acids but sometimes it reacts also.
But the scandium oxide is amphoteric as if the compound can react with acid as well as a base then the compound is said to be amphoteric.
Scandium oxide can react with acid like hydrochloric acid and it can also react with a base like sodium hydroxide. The reaction of scandium oxide with hydrochloric acid is given below:
$S{{c}_{2}}{{O}_{3}}+6HCl+x{{H}_{2}}O\to 2ScC{{l}_{3}}.x{{H}_{2}}O+3{{H}_{2}}O$
The reaction of scandium oxide with sodium hydroxide is given below:
$S{{c}_{2}}{{O}_{3}}+2NaOH\to 2NaSc{{O}_{2}}+{{H}_{2}}O$
So, in both the reactions water is being produced. Therefore, from the above reactions, we can say that scandium oxide is an amphoteric oxide.

Note:
The melting point of scandium oxide is high. Since it has a high melting point, it is used as a substance having resistance to heat and thermal shock. It is also used in electronic ceramics and glass composition.