Question

Which is the correct thermal stability order for H₂E (E = O, S, Se, Te and Po)? 

(1) H₂S < H₂O < H₂Se < H₂Te < H₂Po 

(2) H₂O < H₂S < H₂Se < H₂Te < H₂Po 

(3) H₂Po < H₂Te < H₂Se < H₂S < H₂O 

(4) H₂Se < H₂Te < H₂Po < H₂O < H₂S

Comments

The p block elements, group 15 elements

Answer 1

Ans : (3) H₂Po < H₂Te < H₂Se < H₂S < H₂O

Explanation : 

On going down the group thermal stability order for H₂E decreases,

because H-E H-E bond energy decreases.

Hence, order of stability would be

H₂Po < H₂Te < H₂Se <H₂S < H₂O