# Does NaCl reduce the surface tension of water?

Does NaCl reduce the surface tension of water? And why?

For example soap does it, and I was wondering if NaCl does the same.

• The surface tension of NaCl solution is greater than that of water. – aventurin Apr 16 '16 at 9:59

Negative surface excess means that the compound prefers to stay in the solution rather than on the surface. It has a physical limit, though: the concentration can't be lower than 0. Therefore the effect of such compounds on surface tension is positive, but small (not noticeable with naked eye). This is the case with $\ce{NaCl}$ and pretty much all "normal" inorganic salts.