Question

How many compounds given below are amphoteric oxides?
$P_2{O}_5,P_2{O}_6,A{s}_2{O}_5,A{s}_2{O}_6,S{b}_2{O}_5,S{b}_4{O}_6,B{i}_2{O}_3$

• A. 2
• B. 3
• C. 4
• D. 6

Answer 1

Answer: (A)

The oxides of the type $\stackrel{+3}{E_2}{O}_3$ of $N$ and $P,P_2{O}_3(P_4{O}_6$, dimer of $P_2{O}_3$) are purely acidic, that of As $(A{s}_4{O}_6$, dimer of $A{s}_2{O}_3)$ and $Sb(S{b}_4{O}_6$, dimer of $S{b}_2{O}_3)$ amphoteric and that of $Bi(B{i}_2{O}_3)$ is predominantly basic.
The oxides of the type $\stackrel{+3}{E_2}{O}_5$ are more acidic, e.g. $N_2{O}_5,P_2{O}_5,A{s}_2{O}_5,S{b}_2{O}_5$ So, in the given set of oxides of group- $15$ elements, two oxides are amphoteric, $A{s}_4{O}_6$ and $S{b}_4{O}_6$