Factors Affecting Surface Tension
Category : JEE Main & Advanced
(1) Temperature : The surface tension of liquid decreases with rise of temperature. The surface tension of liquid is zero at its boiling point and it vanishes at critical temperature. At critical temperature, intermolecular forces for liquid and gases becomes equal and liquid can expand without any restriction. For small temperature differences, the variation in surface tension with temperature is linear and is given by the relation
\[{{T}_{t}}={{T}_{0}}(1-\alpha \,t)\]
where \[{{T}_{t}}\], \[{{T}_{0}}\] are the surface tensions at \[{{t}^{o}}C\] and \[{{0}^{o}}C\] respectively and a is the temperature coefficient of surface tension. Examples : (i) Hot soup tastes better than the cold soup.
(ii) Machinery parts get jammed in winter.
(2) Impurities : The presence of impurities either on the liquid surface or dissolved in it, considerably affect the surface tension, depending upon the degree of contamination. A highly soluble substance like sodium chloride when dissolved in water, increases the surface tension of water. But the sparingly soluble substances like phenol when dissolved in water, decreases the surface tension of water.
You need to login to perform this action.
You will be redirected in
3 sec
