What makes the water molecule being undissociated when something is put in water?

Thereby, is the oxygen-hydrogen bond in water the strongest( even stronger than NaCl).

The hydrogen bond in intermolecular force stronger than NaCl??

em... I think it takes some five or six (not sure of the number actually) to tear about an ionic bond... so adding the force up, it may overcome the ionic bond...

but why does some ionic compounds don't disintergrate in water? (like AgCl)

it depends on the bond actually.

according to pauling, Ag's electronegativity is 1.93, while that of Cl is 3, making AgCl not an "ionic" substance. Note: ionic compounds do not exist; it's a technicality.

In an ionic bond one atom has actually torn off the electron of the other atom. The positive ion that's had its electron removed now clings very tightly to the negatively charged ion. When you place them in water they dissociate because the water molecules form rings around the ions. In the case of sodium, the hydrogen of the water molecule faces the chloride (-) ions and the oxygen faces the sodium (+) ions. These polar rings stabilize the ions and it's favorable for the ions to split apart.

 

When the ions are not in a polar liquid they cling very tightly to one another but they are not sharing an electron. So it’s the charge that keeps them together and the stabilizing effect of the polar rings that form around them in a polar liquid that breaks the ions. The water molecules stay together better than the ions when you mix them because the water molecules are still sharing the electrons in their bonds.

In an ionic bond one atom has actually torn off the electron of the other atom.

that is when in solution. NaCl(s) for example is stuck together with all the force of a covalent bond that is considered by pauling to be "ionic". never the less, there is still a hybrid orbital created.