Trying to find the right answer to this..

The p-Block Elements

Question

Arrange the hydrides of group 16 in the decreasing order of their thermal stability. Is the order same or different for their reducing character?

Answer

a) The thermal stability of hydrides decrease on moving down the group this is because of decrease in the bond dissociation enthalpy of hydrides.

H₂O>H₂S>H₂Se>H₂Te>H₂Po

b) Reducing character:
All hydrides of group 16 elements, except H₂O, are reducing agent.
The reducing power of these hydrides increase in going from H₂S to H₂Te, which may be due to increase in the size of the atom and hence decrease in the M-H bond energy.