Question

Which of the following is an amphoteric oxide ?
A. $N{a_2}O$
B. $S{O_2}$
C. ${B_2}{O_3}$
D. $ZnO$

Answer 1

Hint: Most of the elements in the periodic table form binary compounds with oxygen known as oxides . There are different kinds of oxides . Amphoteric oxides are those which react with both acids as well as bases .

Complete step by step answer:
Oxides are classified into simple and mixed oxides .
Simple oxides are further classified into four categories :
Basic oxides - An oxide is said to be basic if it combines with water to form a base .
Acidic oxides - An oxide is said to be acidic if it combines with water to form an acid .
Amphoteric oxides - Oxides which react with both acids and bases are called amphoteric oxides .
Neutral oxides - Oxides which neither react with acids nor base are called neutral oxides .
Further , on moving from left to right in the periodic table , the nature of oxides show a gradual variation from strongly basic through amphoteric to strongly acidic .
On moving down in different groups the variation in oxides is different .
Hence , from the given options $ZnO$ is amphoteric oxide .
So , option D is correct .


Note:
In s - block on moving down the group the basic character of the oxides increases . In p-block on moving down the group the acidic character of the oxide decreases , among non metallic oxides the acidic character increases as the oxidation state of the non metal increases and in d- block the basic character decreases and acidic character increases with increase in the oxidation state of the element .