Why does the surface tension of water increase when #"NaCl"# is dissolved?

1 Answer

Because the NaCl (salt) essentially 'helps' the already strong surface tension of the water due to its electrolytic abilities .

Explanation:

Sodium chloride, is a strong electrolyte, which means it completely dissociates into Na cations, and Cl anions, when placed in H2O. The strong interactions between the Na cations and the partial negative O atoms as well as the Cl anions and the partial positive H atoms, although they disrupt part of the hydrogen bonding that takes place between water molecules, they actually strengthen the water's surface tension because the ion-dipole interactions are stronger than the hydrogen-bonding interactions.