Questions & Answers

Which amongst the following elements can form amphoteric oxide?

Answer Verified Verified
Hint: An amphoteric compound is a molecule or ion that can react both as an acid and as a base. The element is from the 13th group of the periodic table. Now try to answer it accordingly.

Complete step by step answer:
-According to the Bronsted-Lowry theory of acids and bases: acids are proton donors and bases are proton acceptors.
-An amphiprotic molecule can either donate or accept a proton, thus acting either as an acid or a base.
-The common examples of the amphoteric species are water, amino acids, hydrogen carbonate ion, and hydrogen sulfate ion. Since these can donate a proton, all amphiprotic substances contain a hydrogen atom, also, since they can act like an acid or a base, they are amphoteric.
-Amphoteric oxides are those metal oxides which show both the acidic and basic behavior.
Here in these all options Al metal forms aluminium oxide. This $Al_{ 2 }O_{ 3 }$ is an example of an amphoteric oxide, which shows both basic and acidic behavior.
$Al_{ 2 }O_{ 3 }\quad +\quad 6HCl\quad \rightarrow \quad 2AlCl_{ 3 }\quad +\quad 3H_{ 2 }O\quad (Basic\quad nature)$
$Al_{ 2 }O_{ 3 }\quad +\quad 2NaOH\quad \rightarrow \quad 2NaAlO_{ 2 }\quad +\quad H_{ 2 }O\quad (Acidic\quad nature)$

Therefore, we can conclude that the correct answer to this question is option C.

Additional information:
$Al_{ 2 }O_{ 3 }$ is significant in its use to produce aluminium metal, as an abrasive owing to its hardness owing to its high melting point.

-Metals such as copper, zinc, tin, lead, aluminium, and beryllium form amphoteric oxides or hydroxides.
-Amphoteric nature depends on the oxidation states of the oxide.