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 $(C_{2} H_{5} O H)$ and hexane $[C H_{3} (C H_{2})_{4} C H_{3})]$

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Solution

In the above given molecules, only hexane $(C H_{3} (C H_{2})_{4} C H_{3})$ 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 $H_{2} O$ , 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

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Answer the following questions:
As temperature is increased

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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)]

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 $(C_{2} H_{5} O H)$ and hexane $[C H_{3} (C H_{2})_{4} C H_{3})]$