The magnitude of surface tension of liquid depends on the attractive forces between the molecules. Arrange the following in increasing order of surface tension:
Water, alcohol (C2H5OH) and hexane [CH3(CH2)4CH3)]
In the above given molecules, only hexane (CH3(CH2)4CH3)is a non-polar molecule in which only London dispersion forces exist. These forces are very weak while both water and alcohol are molecules in which dipole-dipole interactions as weel as H-bonding exists.
However, H-bonding interactions are much stronger in water than H2O, therefore, it possesses stronger intermo lecules than alcohol and hexane. Hence, the increasing order of surface tension is
hexane < alcohol < water
Greater is the attractive forces between the molecules, greater is the magnitude of surface tension of liquid