If water has the most polar bond of any molecule, why would it be more attracted to the molecules in the container than itself? Why wouldn’t it form a convex meniscus like mercury? Thanks in advance.
I don’t think this is correct. And adhesion can be a function of mechanical, chemical, dispersive, electrostatic, and diffusive mechanisms.
Well I’ve read in multiple sources that, saving some crazy molecule recently forged, water is the most polar molecule. They weren’t Chem textbooks but they seemed like reasonable sites for something that I had a hard time believing would be controversial. HFl is a more polar bond, but the geometry of water makes it the most polar. Still could be wrong I’m sure. Nevertheless, the physics textbook states that the force is a function of molecular attraction so I’m not sure what other forces would be at work.
Ok I get where you’re coming from. The water molecule has a large dipole moment (not the largest, but that’s neither here nor there.) Silica glass has a net zero dipole moment. And if we were only looking at dipole-dipole interactions, you would quite reasonably expect minimal interaction between the glass and water.
But as I alluded to, it’s more complicated than that. I believe there’s a wikipedia article on adhesion, but I don’t know that it goes into this interaction specifically. Keep in mind that while silica comprises a bunch of tetrahedra with Si in the middle and O at the vertices, the surface has dangler oxygens that can get protonated. So you have these polar Si-O-H on the surface that can interact with the water.
The dipole moment of water is something like 1.8 D, that of nitrobenzene like 4.0 D. On the other hand, the surface tension of water is greater than that of nitrobenzene. So it is not just about polarity.
How about the half dozen forces that @Ruken told you are at work?
Mercury doesn’t have a dipole at all, so why do you accept that it should have a convex meniscus?
In checking further into the most polar molecule status, I think I might have figured it out. Even though sio2 is non polar as a whole, the electronegativity difference between si-o is 1.7 vs h-o’s 1.4. I suppose at the margins the h in water will be more attracted to the O’s in the glass than water.