Describe what happens to NaCl when placed in water.

u mean what happens to the cell. i believe that NaCl is a hypotonic solution and if cells are placed into it the cell will burst.

Water molecules break the ionic bonds holding Na+ and Cl- together. Each sodium ion becomes surrounded by polar water molecules, with the electronegative ends of water molecules interacting with the ion. Each chloride ion also becomes surrounded by polar water molecules, but in this case it is the electropositive ends of the water molecules that bind to the ion. A consequence is that sodium and chloride ions can function relatively independently of each other when in solution.

First you have to look at the properties of H20. Due to dipole-dipole interactions, the O on H2O is partially negative and the two H's are partially positive.

This causes the Na+ to be attracted to the partially negative O on the water molecule and the Cl- ion

The Cl- is attacted to the partially positive H on water and the Na+ ion

The ionic bond between Na and Cl is very strong and one hydrogen bond will not break it. However, due to the combined force of many hydrogen bonds, the ionic bond between Na and Cl break which causes dissociation