Question

Which is the most VISCOUS?

• A. Ethylene Glycol
• B. Methanol
• C. Glycerol
• D. Ethanol

Answer 1

The Correct Option is C

Viscosity refers to a fluid's resistance to flow. Glycerol, also known as glycerin or glycerine, has a higher viscosity compared to the other compounds listed. It is a thick, syrupy liquid with a relatively high molecular weight and strong intermolecular forces, which contribute to its higher viscosity.

Ethylene glycol (A) is also a viscous liquid, but its viscosity is generally lower than that of glycerol.

Methanol (B) and ethanol (D) have lower viscosities compared to both glycerol and ethylene glycol.

Therefore, the most viscous compound among the options provided is glycerol (C).

Answer 2

Correct Answer: Glycerol 

Explanation:
Viscosity refers to the resistance offered by a liquid to flow. A liquid with higher viscosity flows more slowly.

Among the given substances:
• Methanol and Ethanol are alcohols with a single –OH (hydroxyl) group.
• Ethylene Glycol has two –OH groups.
• Glycerol has three –OH groups.

The presence of hydroxyl groups enables hydrogen bonding between molecules. More hydroxyl groups result in stronger intermolecular forces, which increases viscosity.

Since Glycerol contains three hydroxyl groups, it forms more hydrogen bonds and flows more slowly than the others. 

Therefore, Glycerol is the most viscous among the options.