Question

Which one of the following cannot form an amphoteric oxide?
A.$Al$
B.$Sn$
C.$Sb$
D.$P$

Answer 1

At first think about the word amphoteric. An amphoteric compound is a molecule or ion that can react both as an acid and as a base. Amphoterism depends on the oxidation states of the oxide. Many metals form amphoteric oxides or hydroxides.

Complete step by step answer:
The most common example for an amphoteric oxide is $A{l_2}{O_3}$. We all know that aluminium forms amphoteric oxide as it acts as both acid and base in a chemical reaction. Aluminium, tin, lead, copper, zinc and beryllium form amphoteric oxides. These substances are acid-base indicators.
$Sn$ and $Sb$ form amphoteric oxides as the oxides of these are partial ionic as well as partial covalent.
Phosphorus cannot form amphoteric oxides because it only forms covalent oxides. We all know that covalent oxides are acidic in nature.
So the answer is D.

Additional Information:- One type of amphoteric species are amphiprotic molecules, which can either donate or accept a proton. Examples include amino acids and proteins.
Ampholytes are amphoteric molecules that contain both acidic and basic groups and will exist mostly as zwitterions in a certain range of $pH$. The $pH$ at which the average charge is zero is known as the molecule's iso electric point. Ampholytes are used to establish a $pH$ gradient for use in iso electric focusing.

Note:
Metal oxides which react with both acids as well as bases to produce salts and water are known as amphoterIc oxides. Acids donate protons, bases accept protons but amphoteric substances can do either.