The qualitative sketches I, II and III given below show the variation of surface tension with molar concentration of three different aqueous solutions of KCl, $C H_{3} OH$ and $C H_{3} (C H_{2})_{11} OS O_{3}^{-} N a^{+}$ at room temperature. The correct assignment of the sketches is

Question

TestHub · Accepted Answer

Impurities affect surface tension appreciably. It is observed that impurities which tend to concentrate on surface of liquids, compared to its bulk lower the surface tension.

Substances like detergents and soaps $[{CH}_{3} {({CH}_{2})}_{11} {SO}_{3}^{-} {Na}^{+}]$ decrease the surface tension sharply.

Those like alcohol (eg. $C H_{3} OH, C_{2} H_{5} OH$ ) lower the surface tension slightly.

Inorganic impurities present in bulk of a liquid such as $KCl$ tend to increase the surface tension of water.

Chemistry - Surface Chemistry Question with Solution | TestHub

Options:

Doubts & Discussion