Which of the following statements is NOT correct about surface tension?

Correct option is C

The correct answer is (c) At room temperature, surface tension of water is less than ethyl alcohol.

• This statement is NOT correct. At room temperature, the surface tension of water is actually higher than that of ethyl alcohol.
• Water has a surface tension of approximately 72.8 dynes/cm at room temperature, whereas ethyl alcohol has a lower surface tension of around 22.3 dynes/cm.
• Surface tension is indeed measured in dynes/cm, and the cohesive forces between liquid molecules are responsible for this phenomenon.
• The spherical shape of water droplets is due to surface tension, which minimizes the surface area of the liquid.

Information Booster:

Surface Tension:

• A physical property arising due to the cohesive forces between molecules at the surface of a liquid.
• Measured in units like dynes/cm or N/m.
• Responsible for phenomena like the formation of droplets, capillary action, and the ability of insects to walk on water.

Cohesive Forces:

• The attraction between molecules of the same substance.
• These forces contribute to surface tension by pulling the molecules at the surface inward, creating a "skin" on the liquid surface.

Comparison of Surface Tension:

• Water has a high surface tension compared to many other liquids due to strong hydrogen bonding.
• Ethyl alcohol, with weaker intermolecular forces, has a significantly lower surface tension than water.