Which of the following pairs will not exhibit diffusion?
Salt, sand
Explanation of the correct option:
(C) Salt, sand
Explanation of incorrect options:
(A): Hydrogen, oxygen
Because hydrogen and oxygen are in the gaseous state of matter, they have the potential to move even with little amounts of matter in terms of flow, and they disperse easily in the air.
(B): Oxygen, water
Oxygen and water are not the correct answers because they are in the gaseous and liquid states of matter, respectively, which have enough kinetic energy and pressure to easily disperse in the air, whereas solid-state matter cannot.
(D): Sugar crystals, water
Sugar crystals can be dissolved in water, which is a liquid state of matter. Because they are loosely packed particles, liquid states of matter can undergo diffusion.
Hence, the correct option is C i.e. Salt, sand.