Question

If a perfume bottle is opened at one end of a room, the odor will quickly be detected on the other side of the room. Why?
A.The molecules are diffusing.
B.The molecules are being compressed.
C.Your sense of smell improves.
D.The molecules are condensing.

Answer 1

Hint: When a bottle of perfume is opened at one end of the room, the smell soon spreads on the whole room. We know that a gas is at constant motion so it moves slowly throughout the room due to which the smell spreads throughout the room.

Complete step by step answer:
If a perfume bottle is opened at one end of a room, the odor will quickly be detected on the other side of the room. The reason behind this is diffusion.
The gas present in the form of perfume is at higher concentration inside the bottle.
When the bottle is opened the gases from inside the bottle are released from higher concentration to lower concentration.
We know that molecules of gases in the air are at constant motion.
So the particle travels from higher concentration level to lower concentration level and spreads across the room due to which the odour can be detected from the other side of the room. This process is called diffusion.
If molecules were condensed or compressed they wouldn’t have spread across the room.

Hence the correct answer is option A.

Note:
Many students get confused between diffusion and osmosis as both involve the movement of particles. But they are different as explained below-
-Diffusion is free intermixing of molecules of different substances where no semi-permeable membrane is required while in osmosis only solvent particles can diffuse and a semipermeable membrane is required.
-Diffusion cannot be stopped but osmosis can be prevented or reversed.
-Diffusion is for gases and liquids both but osmosis only occurs in liquids.