All the hydrides (of group- 16 elements) except one possess reducing property and this character increases  from H₂S to H₂Te. Identity the hydrides

Among the following, the hydride which is not a reducing agent is H₂O. Except H₂O all others are reducing agent. The reducing nature of an atom or compound depends on how easily it donates or released electrons.

The reducing nature of hydrides increases down the group, so the order is H₂O< H₂S <H₂Se <H₂Te