Question

what happens the average kinetic energy of water molecules as water freees

Answer 1

Well when something is a solid it is tightly compacted, so `beforehand when the water was a liquid the molecules were more spaced out, but now it froze so the molecules are more compacted together, and move is a sort of vibrating path. They still have kinetic energy because they are not sitting still, like I said, they still "vibrate".

Answer 2

The answer to your question is 'Nothing'.

The average kinetic energy of a molecule is proportional to the absolute temperature and since the water and ice are both at 273K when freezing occurs, the water molecules have the same kinetic energy in both phases.