Question

Giving suitable reasons, arrange the hydrides of group 16 elements in the increasing order of their acidic character.

Answer 1

1. The acidic character of group 16 hydrides increases down the group: H₂O < H₂S < H₂Se < H₂Te.
2. This is because the \[\ce{M - H}\] bond strength decreases down the group due to the increasing size of the central atom.
3. Weaker \[\ce{M - H}\] bonds break more easily, releasing H⁺ ions and increasing acidity.
4. Water is least acidic, as its \[\ce{M - H}\] bond is strongest and it has hydrogen bonding.
5. H₂Te is the most acidic due to the weakest \[\ce{M - H}\] bond and easiest proton release.

Thus, acidity increases in the order: H₂O < H₂S < H₂Se < H₂Te.