Correct Answer - Option 1 : Only cohesive force
CONCEPT:
Surface tension:
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Surface tension is the property by virtue of which liquid tires minimize their free surface area.
- In a spherical shape, the surface area is minimum and for this reason, the raindrops are spherical.
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Surface tension is measured as the force acting per unit length of an imaginary line drawn on the liquid surface
\(Surface\;tension = \frac{{Force}}{{length}}\)
Two factors can affect the surface tension of a liquid. The factors are;
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Temperature: If temperature increases then the surface tension of a liquid decreases.
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Soluble Impurities: In the case of less soluble impurities, the surface tension decreases. But, for highly soluble impurities in the liquid the surface tension increases.
EXPLAINATION:
- The cohesive forces between molecules in a liquid are shared with all neighboring molecules.
- Those on the surface have no neighboring molecules above and, thus, exhibit stronger attractive forces upon their nearest neighbors on and below the surface.
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Surface tension could be defined as the property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of the water molecules. Hence, option (1) is correct.
