Intermolecular Forces and Physical Properties of Pure Substances

Which has the highest normal freezing point?
a.O2
b.N2
c.H2
d.NH3
Which has the lowest enthalpy of fusion?
a.H2O
b.Li2O
c.HCl
d.HF
Which has the least heat of vaporization?
a.H2Te
b.Xe
c.H2Se
d.H2O
Which has the highest normal boiling point?
a.C2H6
b.NH3
c.Li2O
d.CH4
Which has the smallest vapour pressure at 25°C?
a.O3
b.SiO2
c.CO2
d.H2O