Sodium chloride (NaCl) is very soluble in water (360,9 g/L at 20 0C) but is not soluble in petrol.
You reach the solubility of salt in water when the salt stops dissolving and settles at the bottom, no matter how hard you try to mix it. You can increase solubility by increasing the water temperature.
In presence of salt the crystals grow faster because the solubility of salt decreases the solubility of any other compound in water.
Adding water to salt, is not increasing solubility, it is increasing the ammount of solvent, and thereby increasing the ammount of salt in solution :).
The volume solution in conical flask is very important in solubility ionic salt water. This is because it determines its solubility.
Salt dissolves more easily than sugar, in my experience. But the solubility is similar. :)
Solubilization of salt in water is a physical change.
Solubility
It is an isotopic effect on solubility; the normal water is H2O or the heavy water is D2O.
Salt in water is an example of solubility.
As the temperature increases, the solubility of salt (sodium chloride) will increase. At 20 degrees C, the solubility of sodium chloride is 35.76g/100mL water and at 100 degrees C, the solubility is 39.1g/100mL water. Refer to the related links for more information.
Solubility
If by "salt" you mean sodium chloride, then YES, it is most definitely soluble.