Answer:
1.
Water has a high boiling point considering its low molecular weight.
This is because the O-H bonds are very polar and the H's are located at two corners of a tetrahedron giving water a high molecular polarity so that they tend to stick together.
2.
Water forms hydrogen bonds between molecules
these bonds are rather flexible so that in liquid phase the molecules are relatively close together
but as the hexagonal arrangement of ice is formed the bonds are licked in place and as a result the average distance between molecules actually increases
with the result that ice is less dense than liquid water
Explanation:
