Which physical property is primarily responsible for preventing liquids from separating in a container?

• A. Surface tension
• B. Vapor pressure
• C. Density
• D. Boiling point

Answer: (A)

Verified step by step guidance

1. Understand that the question asks about the physical property that keeps liquids from separating inside a container, meaning it relates to how the liquid molecules interact at the surface or interface.
2. Recall that surface tension is a property caused by the cohesive forces between liquid molecules at the surface, which acts like a 'skin' preventing the liquid from easily separating or breaking apart.
3. Consider the other options: vapor pressure relates to evaporation rate, density is mass per volume and affects layering but not cohesion, and boiling point is the temperature at which a liquid turns to gas, which does not prevent separation.
4. Recognize that surface tension arises because molecules at the surface experience a net inward force, pulling them together and maintaining the liquid's integrity.
5. Conclude that surface tension is the primary physical property responsible for preventing liquids from separating in a container.