Question

Describe the factors that affect viscosity? (Select which of the following statements are true. Select all that apply.)
A) Hydrogen bonds increase viscosity because they increase the liquid's intermolecular forces, making it more resistant to flow.
B) Hydrogen bonds decrease viscosity because they decrease the liquid's interactions between molecules.
C) Viscosity increases with temperature.

Answer 1

Viscosity is the ability of the liquids, gases, or substances to resist the flow. Liquids that flow very slowly are said to have high viscosities. The substances that flow easily off the surface are said to have low viscosities.

Complete Step By Step Answer:
Viscosity is the tendency of a fluid to resist its flow, or any change in its shape or motion. The internal forces or friction plays an evident role, when one layer of the fluid moves over the another. More the friction, more amount of force required for the layers to flow over each other. This is known as shearing. Due to this the fluids with high viscosity required more force than the liquids with less viscosity.
Viscosity is governed by the strength of the intermolecular forces and also the shape of the molecules. The liquid molecules that can form Hydrogen bonds and are polar have more viscosity than the non-polar liquids. Example Honey, glucose, fructose have high viscosities due to hydrogen bonding. Also, molecules with a long chain of molecules have high viscosities. As their molecular chains get tangled to each other, it becomes difficult to untangle them and flow. Example Fuel Oil, Lubricating grease, etc.
The viscosity in gases increases with the increase in temperature, as the molecules of gases flow easily and with the increase in temperature flow more sluggishly. Whereas in liquids, the additional forces between the molecules become important, hence viscosity tends to decrease in liquids with increase in temperature.
Hence statement A is only correct.

Note:
Viscosity plays an important role in lubrication. Lubricating agents like oil and grease have low viscosity and flow slowly. At low temperatures the viscosity is too high and it cannot be pumped, hence cannot be used for lubrication. A moderate viscous liquid is used for lubrication.