Questions on Surface Tension
20 Multiple-Choice Questions on Surface Tension
1. What is surface tension?
A) Force applied parallel to a surface
B) The resistance to flow
C) The energy required to increase the surface area of a liquid
D) The weight of a liquid surface
E) The friction between two fluids
2. Surface tension is primarily caused by:
A) Gravity
B) Cohesive forces between molecules
C) Adhesive forces to container walls
D) Kinetic energy of gas molecules
E) Vapor pressure
3. Which of the following liquids has the highest surface tension at room temperature?
A) Ethanol
B) Acetone
C) Mercury
D) Water
E) Olive oil
4. The SI unit of surface tension is:
A) N/m
B) J/kg
C) Pa·s
D) N·s/m²
E) kg/m²
5. Which property of water allows insects to walk on its surface?
A) Low viscosity
B) Capillary action
C) High surface tension
D) Low boiling point
E) High vapor pressure
6. What happens to surface tension as temperature increases?
A) Increases
B) Decreases
C) Stays constant
D) Becomes infinite
E) Converts to pressure
7. Soap reduces the surface tension of water by:
A) Increasing hydrogen bonding
B) Increasing kinetic energy
C) Disrupting cohesive forces
D) Decreasing adhesion
E) Reducing pressure
8. The spherical shape of small liquid droplets is due to:
A) Gravity
B) Adhesive forces
C) Surface tension minimizing surface area
D) Air resistance
E) Capillary action
9. Which of the following reduces surface tension the most?
A) Heating the liquid
B) Adding salt
C) Adding a surfactant
D) Stirring vigorously
E) Increasing pressure
10. What role does surface tension play in capillary action?
A) It resists the rise of liquid
B) It causes liquids to boil
C) It helps liquid climb up narrow tubes
D) It increases evaporation
E) It decreases adhesion
11. The inward pull of molecules on the surface of a liquid creates:
A) Buoyancy
B) Pressure
C) Surface tension
D) Density
E) Heat capacity
12. A liquid with high surface tension would:
A) Spread easily over a surface
B) Form flat droplets
C) Be difficult to pour
D) Be more volatile
E) Form rounder droplets
13. The addition of detergent to water:
A) Increases boiling point
B) Increases surface tension
C) Decreases surface tension
D) Raises vapor pressure
E) Makes water more viscous
14. Which of these observations best demonstrates surface tension?
A) Water boiling
B) Ice melting
C) A water strider standing on water
D) Evaporation of alcohol
E) Freezing of a lake
15. Surface tension is stronger in:
A) Gases than liquids
B) Water than mercury
C) Liquids than solids
D) Mercury than water
E) Water vapor than water
16. What kind of bonds are mainly responsible for the high surface tension of water?
A) Ionic bonds
B) Covalent bonds
C) Hydrogen bonds
D) Van der Waals forces
E) Metallic bonds
17. Capillary action is a result of:
A) Adhesion only
B) Cohesion only
C) Surface tension only
D) Adhesion and cohesion
E) Pressure differences only
18. Surface tension affects which of the following most directly?
A) The color of a liquid
B) The boiling point
C) The shape of small liquid drops
D) The mass of a liquid
E) The molar concentration
19. Which substance would you expect to have the lowest surface tension?
A) Water
B) Mercury
C) Oil
D) Soap solution
E) Ethylene glycol
20. When a liquid has low surface tension, it:
A) Forms droplets easily
B) Spreads easily over surfaces
C) Has strong cohesive forces
D) Has a high boiling point
E) Cannot mix with other liquids
- Questions on Gas Pressure
- Questions on Atmospheric Pressure
- Questions on Pressure Units and Conversions
Answers with Explanations
1. C – Surface tension is the energy required to increase the surface area of a liquid.
2. B – Surface tension arises from cohesive intermolecular forces.
3. C – Mercury has the highest surface tension due to strong metallic bonding.
4. A – Surface tension is measured in newtons per meter (N/m).
5. C – High surface tension allows insects to stand on water.
6. B – As temperature increases, surface tension decreases due to weakened cohesive forces.
7. C – Surfactants disrupt cohesive forces, reducing surface tension.
8. C – Droplets are spherical due to surface tension minimizing surface area.
9. C – Surfactants (like soap) significantly reduce surface tension.
10. C – Surface tension, along with adhesion, enables capillary action.
11. C – This inward pull at the surface is what creates surface tension.
12. E – High surface tension leads to rounder droplet formation.
13. C – Detergents lower water’s surface tension, aiding cleaning.
14. C – Water striders walking on water is a classic surface tension example.
15. D – Mercury has higher surface tension than water.
16. C – Hydrogen bonding between water molecules creates high surface tension.
17. D – Capillary action results from both cohesion and adhesion.
18. C – Surface tension shapes small droplets.
19. D – Soap solution has low surface tension due to surfactants.
20. B – Low surface tension liquids spread easily.
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