Why does water break salt really
1.) The covalent OH bond strength in water is slightly stronger than the NaCl ionic bond strength.  

2.) Water might be neutral but each atom exhibits a partial charge.  Oxygen sucks up most of the electron density away from the hydrogen atoms leaving O with a partial negative charge and hydrogen with a partial positive charge.  This gives rise to the famous hydrogen bonding behavior of water.

3.) You would have to analyze the energies of each of the interacting components to know. 

4.) Cl is more electronegative than Na due to the larger number of protons in the nucleus.  This means that Cl will suck electron density away from Na as opposed to the other way around.