Question

Name the process associated with the following:
(a) Dry ice is kept at room temperature and at one atmospheric pressure.
(b) A drop of ink placed on the surface of water contained in a glass spreads throughout the water.
(c) A potassium permanganate crystal is in a beaker and water is poured into the beaker with stirring.
(d) An acetone bottle is left open and the bottle becomes empty.
(e) Milk is churned to separate cream from it.
(f) Settling of sand when a mixture of sand and water is left undisturbed for some time.
(g) Fine beam of light entering through a small hole in a dark room, illuminates the particles in its paths.

Answer 1

Hint: The process of converting a solid directly into a gas is called sublimation. The process of spreading or distribution of chemical high concentration to low concentration is called diffusion. The evaporation of a chemical is going to depend on the boiling point of it.

Complete answer:
- In the question it is asked to name the given process associated with each statement.
 (a) Dry ice is kept at room temperature and at one atmospheric pressure: dry ice undergoes sublimation (solid phase to gaseous phase) process at room temperature.
(b) A drop of ink placed on the surface of water contained in a glass spreads throughout the water: The ink is going to move from high concentration to low concentration called diffusion.
(c) A potassium permanganate crystal is in a beaker and water is poured into the beaker with stirring: This process is called dissolution means we are going to make the potassium permanganate to dissolve in water by adding water with stirring.
(d) An acetone bottle is left open and the bottle becomes empty: The boiling point of acetone is very less. So, it is going to evaporate at room temperature.
(e) Milk is churned to separate cream from it: At the time of churning of milk the centrifugal force is going to act and make the cream to stick on the walls of the container.
(f) Settling of sand when a mixture of sand and water is left undisturbed for some time: The sand is going to settle at the bottom of the vessel due to the process of sedimentation.
(g) Fine beam of light entering through a small hole in a dark room, illuminates the particles in its paths: The scattering of light when it is passed through a dark room is due to the Tyndall effect because of the presence of air in the dark room.

Note:
The air causes the light to scatter when the light is passed through it. The process of scattering is due to the process of Tyndall effect. The sand is heavier in nature and not soluble in water. So, the sand is going to be sedimented in the water if it is not disturbed for some time.