Hint:Sublimation is one of the phase transitions in which a solid is converted into gaseous form. When solid is converted into gases then the force of attraction between the molecules decreases therefore the molecules of the compound move freely.
Complete step-by-step answer:Sublimation is defined as one of the phase changes that convert solid state into gaseous state. As we know that solid substances consist of particles that are held together by strong force of attraction. Then this conversion takes place from solid to gases, and then the force of attraction becomes weak and the distance between the particles increases. In gaseous form, the particles are more freely to move and there will be a very weak force of attraction between them.
Iodine is a substance which is present in a crystalline form. When this iodine is heated, it converts it into a gaseous form. The sublimation of iodine takes place in the presence of air or oxygen, the particles overcome the force of attraction between them and therefore sublimation takes place. Iodine contains weak Van Der Waals forces and therefore it easily converts it into gaseous form.
The sublimation of iodine is an example of physical change because change of states takes place in this process. In the process of sublimation of iodine, now chemical bonds are broken and the iodine molecule remains as a discrete entity.
Let us see the reaction:
${{I}_{2\left( s \right)}}\xrightarrow{\Delta }{{I}_{2\left( g \right)}}$
Note:A physical change is defined as the change when a substance undergoes change in physical properties like shape, state, size, colour and appearance but the chemical composition remains intact. In physical change, no new substance is formed and most of this change is reversible.
