51.

The heat of vaporisation of water at 100°C is 40·6 kJ per mole and that of benzene at 80°C is 31kJ per mole. Which out of the two has stronger attractive forces ?

Why vegetables are cooked with difficulty at a hill station?

Arrange water, benzene and acetone in order of increasing boiling point. 

Vapour pressure of ether and alcohol is higher than water. Why?

Arrange ether, water and ethyl alcohol in order of decreasing intermolecular attractive forces.

What is the difference between a normal boiling point and standard boiling point ?

Name two compounds which lower the surface tension of water.

Insects can walk on the surface of water. Why?

Why can a glass be filled above its rim with water?

What is the effect of temperature on: (i) surface tension (ii) viscosity.