# Why is the viscosity of water and ethanol lower than that of a water-ethanol mixture?

We found in an experiment using Ostwalds method that ethanol is more viscous than water, which is already surprising as water has stronger intermolecular bonds than ethanol as @MaxW pointed out.

The mixture of both substances furthermore is significantly more viscous than both individual substances. This is interesting. We did not come up with a satisfying explanation for this behaviour.

I know that one shouldn't expect that a mixture behaves the same way or proportional to the concentration of the components, but I would appreciate an explanation of this effect on a molecular level.

• Ethanol boils at $\pu{78 ^\circ C}$ and water boils at $\pu{100 ^\circ C}$. I'd say that water has stronger intermolecular bonds. – MaxW Apr 19 '20 at 20:25
• @MaxW You're right.. I corrected this. Thank you. – TheoreticalMinimum Apr 19 '20 at 20:39