Question

What type of oxide would Eka-aluminum (Gallium) form?
(a)- \[Ga{{O}_{3}}\]
(b)- \[G{{a}_{2}}{{O}_{3}}\]
(c)- \[G{{a}_{3}}{{O}_{2}}\]
(d)- \[GaO\]

Answer 1

Hint: Eka-aluminium (Gallium) is the element of group 13. It belongs to the boron family. There are 3 valence electrons in the outermost shell of the Gallium. It would form oxide the same as that of Aluminium.

Complete answer: Gallium is the element that belongs to group 13. Group 13 is the boron family.
Gallium is the third element of the boron family. Its atomic number is 31.

The electronic configuration of Gallium is \[1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}3{{d}^{10}}4{{s}^{2}}4{{p}^{1}}\]
There are 3 electrons in its outermost shell so it shows a +3 oxidation state mostly.
All the metals of group 13 react with oxygen at high temperature to form trioxides of the formula \[{{M}_{2}}{{O}_{3}}\],
\[4M(s)+3{{O}_{2}}\to 2{{M}_{2}}{{O}_{3}}(s)\]
Where M is the metal of group 13.
The reactivity of the elements of group 13 towards dioxygen increases down the group.
So, for Gallium the reaction will be:
\[4Ga(s)+3{{O}_{2}}\to 2G{{a}_{2}}{{O}_{3}}(s)\]

Hence, it forms oxide of formula \[G{{a}_{2}}{{O}_{3}}\]
So, the correct answer is an option (c)- \[G{{a}_{2}}{{O}_{3}}\]

So, the correct answer is “Option C”.

Additional Information: As we know that the reactivity of the elements of group 13 increases down the group.
Hence boron is unreactive in the crystalline form. Aluminium does not react with dry air. However, in moist air, its surface gets tarnished (appears dull) due to the formation of a very thin oxide layer on the surface which protects the metal from further attack.
The air contains nitrogen also but Gallium does not react with nitrogen.
Boron and aluminium react with nitrogen to form nitrides.
\[\begin{align}
  & 2B+{{N}_{2}}\to 2BN \\
 & 2Al+{{N}_{2}}\to 2AlN \\
\end{align}\]

Note: Don’t get confused between option (b) and (c), because the oxidation state of gallium is +3. So in the oxide form of gallium, 3 atoms would be of oxygen and not gallium. Gallium is very reactive towards oxygen, it can even react in dry air.