Which molecules would most likely cause a liquid to have the lowest viscosity?

• A. Large, polar molecules
• B. Small, nonpolar molecules
• C. Small, polar molecules
• D. Large, nonpolar molecules

Answer: (B)

Verified step by step guidance

1. Understand that viscosity is a measure of a liquid's resistance to flow, which depends on the strength of intermolecular forces and the size of the molecules involved.
2. Recognize that large molecules tend to have higher viscosity because their size increases friction and entanglement between molecules.
3. Consider polarity: polar molecules have stronger intermolecular forces (like hydrogen bonding or dipole-dipole interactions), which increase viscosity.
4. Small molecules generally have lower viscosity because they experience less friction and have weaker intermolecular forces compared to larger molecules.
5. Combine these ideas to conclude that small, nonpolar molecules, which have weak intermolecular forces and small size, will most likely cause a liquid to have the lowest viscosity.