(a) Using VSEPR theory predict the probable structures of the following :
(b) Arrange the following groups of substances in the order of the property indicated against each group :
(i) - increasing order of boiling points.
(ii) O, S, Se, Te - increasing order of electron gain enthalpy with negative sign.
(iii) - increasing order of bond dissociation enthalpy.
(iii) The increasing order of bond dissociation enthalpy is :