Question

which molecules would most likely cause a liquid to have the lowest viscosity?
large, polar molecules
small, nonpolar molecules
small, polar molecules
large, nonpolar molecules

Explanation:

Viscosity is related to the intermolecular forces and molecular size. Smaller molecules have less resistance to flow, and nonpolar molecules have weaker intermolecular forces (like London dispersion forces, which are weaker than dipole - dipole or hydrogen bonding in polar molecules). Large molecules or polar molecules (with stronger intermolecular forces) would lead to higher viscosity as they interact more strongly or have more bulk to impede flow. So small, nonpolar molecules would result in the lowest viscosity.

Answer:

B. small, nonpolar molecules