Question

naphthalene balls disappears with time without leaving any solid? give reason

Answer 1

a) Naphthalene balls undergo sublimation due to which it converts directly into vapours and disappear into air without leaving any solid. (b) The particles of perfume diffuse rapidly into the air and its smell can be felt while sitting several metres away.

Answer 2

Naphthalene balls have a property of a sublimate I.e. they turn into gaseous state from solid state without turning into liquid state and vice versa.
That is why naphthalene balls undergo sublimation and diffuse directly into the atmosphere by converting to gaseous state