naphthalene balls become smaller day by day.why?
Naphthalene, while changing its state, does not go from solid to liquid to gaseous state. It sublimes, that is it goes directly from the solid state to the gaseous state. The bonds between the naphthalene molecules are sufficiently weak and even heat from ordinary room temperature is sufficient to break the intramolecular forces and move apart. The freed molecules, especially from the surface, can go into the gas phase immediately. This is the reason, the naphthalene balls become smaller in size day by day.