Question

Camphor disappears if kept in open air for a few days why

Answer 1

camphor is a sublimative substance.
That is it converts dicertly to gas from solid.
Hence is does not disappear but actually evaporate

Answer 2

Answer:

"Camphor" is a "sublimatory substance" i.e., it goes through the "process of sublimation" in which a solid substance directly gets converted into its "gaseous phase" without going through its "intermediate liquid phase". Any substance is made of atom and molecules whose particles have by strong "inter molecular forces of attraction" between them. If these forces are weak, the particles can be separated easily, with small amount of energy. This happens in the case of camphor which gains this energy from the atmosphere and converts into its vapour phase.