Arrange the following :
`NaH, MgH_2, H_2O` (in order of increasing bond dissociation enthalpy)

Arrange the following species in the decreasing order of their bond dissociation enthalpies : O_(2),O_(2)^(+) and O_(2)^(-)

Arrange the following (i) CaH_(2), BeH_(2) and TiH_(2) in order of increasing electrical conductance. (ii) LiH, NaH and CsH in order of increasing ionic character. (iii) H–H, D–D and F–F in order of increasing bond dissociation enthalpy. (iv) NaH, MgH_(2) and H_(2)O in order of increasing reducing property.

i. Arrange the following in decreasing order of bond dissociation enthalpy F_(2) , Cl_(2) , Br_(2) , I_(2) ii. Bi does not form pπ-pπ bonds. Give reason for the observation. iii.Electron gain enthalpy of oxygen is less negative than sulphur. Justify