NCERT Questions – 3 (b)

Give reason for the following observations.

(b) We can get the smell of perfume sitting several metres
away.

Answer:

• Volatility: Perfumes contain volatile substances, meaning they evaporate quickly at room temperature.
• Diffusion: The perfume molecules mix with the air and spread in all directions due to diffusion.
• As these molecules reach our nose, we can detect the fragrance even from a distance.
• This is the same reason why we can smell food cooking from another room.