Why is iodine a different colour in different solutions?
Iodine in water is a dirty brown ikky color due to the polar water molecules' attraction for the iodine atoms since they are polar, too, due to instantaneous dipole-induced dipole attractions. In hexane, however, iodine is a violet color because hexane is a non-polar solvent.
The difference in color of iodine in different solutions can be explained by its interaction with the solvent molecules and the resulting molecular arrangement.
In water, iodine appears as a dirty brown color. This is because water is a polar solvent, meaning it has a positive and negative end. When iodine is mixed with water, the polar water molecules attract the iodine atoms due to their opposite charges. This results in the formation of temporary bonds, known as instantaneous dipole-induced dipole attractions, between the water molecules and the iodine atoms. These temporary bonds cause the iodine to dissolve in water and give it a brown color.
On the other hand, in a non-polar solvent like hexane, iodine appears as a violet color. Non-polar solvents do not possess distinct positive or negative ends like polar solvents do. This means that the iodine molecules in hexane are not attracted to the solvent molecules in the same way as in water. Instead, iodine molecules in hexane tend to interact with each other, forming a molecular arrangement that results in the violet color.
To summarize, the difference in color of iodine in different solutions is due to the nature of the solvent and its interaction with the iodine molecules. In polar solvents, iodine atoms are attracted to the solvent molecules, resulting in a brown color. In non-polar solvents, iodine molecules interact with each other, giving rise to a different color, such as violet.