1. A gas has no definite shape or volume of its own. It acquires the shape of the container.
Reason: Intermolecular attraction is the weakest in gases whereas intermolecular separation is the largest. Hence, molecules in a gas move very fast and the gas expands to fill all the space available.
2. A gas has no surface of its own.
Reason: Molecules escape from an open container.
3. A gas is not rigid and is easily compressed.
Reason: Intermolecular separation is very large in gaseous state which can be decreased by applying pressure.
4. A gas can diffuse into another gas.
Reason: Molecules in a gas move very fast. Hence the speed of diffusion is very large.
5. A gas on cooling changes into liquid state.
Reason: Cooling reduces intermolecular separation and increase intermolecular force of attraction.
6. A gas can flow in all directions. It requires a vessel closed from all sides.
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