Why does the temperature of a substance not rise during a change of state?

Give reasons for the following:
$(a)$ Water droplets appear on the outer surface of a tumbler containing ice-cold water.
$(b)$ People prefer to wear cotton clothes in summer.
$(c)$ On a hot sunny day,people sprinkle water on the roof or open ground.

What happens when you open a bottle of perfume?

Archit dropped a crystal of potassium permanganate into two beakers $A$ and $B$ containing hot water and cold water respectively. After keeping the beakers undisturbed for some time,what did he observe and why?

Fill in the blanks :
$(a)$ Evaporation of a liquid at room temperature leads to a ........... effect.
$(b)$ At room temperature,the forces of attraction between the particles of solid substances are ........... than those which exist in the gaseous state.
$(c)$ The arrangement of particles is less ordered in the ........... state. However,there is no order in the ........... state.
$(d)$ ........... is the change of solid state directly to vapour state without going through the ........... state.
$(e)$ The phenomenon of change of a liquid into the gaseous state at any temperature below its boiling point is called ...........

Give reasons for the following:
$(i)$ $A$ gas exerts pressure on the walls of the container.
$(ii)$ $A$ gas fills the vessel in which it is kept.