Verified answer

Answer:

Naphthalene

Explanation:

Answer: (a): Naphthalene balls disappear with time without leaving any solid because they undergo sublimation i.e., they directly change into vapour without passing through the liquid state. (b): We can get the smell of perfume sitting several metres away due to diffusion.

Ans. (a) Naphthalene balls disappear with time without leaving any solid, because naphthalene balls sublime and directly changes into vapour state without leaving any solid.

Answer. We can get the smell of perfume sitting several metres away due to diffusion. Vapours of perfume move rapidly in all directions and spread in the air by diffusion. When perfume vapours reach several metres away we can get the smell of perfume.