Question

a mother preserves woolen clothes using napthalene balls which disappear after some time,give reasons

Answer 1

By absorbing heat energy from the surroundings, naphthalene balls slowly sublime, i.e.,solid naphthalene balls directly get converted into vapours and disappear with time without leaving any solid.

Answer 2

this happens because of a process called diffusion. in this process solid state directly changes into gaseous state without coming in liquid form. by absorbing heat energy from the surroundings the balls get sublimise...