h-bonds in water:cohesive solubility occurs because:water water interactions are replaced by more energetically favourable water-solute interactions water:nearly tetrahedral structure h-o-h bond angle :104.5 degree h-bond 10%covalent 90% ionic life time of each h-bond 1-20 pico seconds in ice each water molecule forms a maximum of 4 hydrogen bonds this generates a crystal lattice this crystal lattice makes ice less dense than water and hence it floats on water