Which of the following is an example of sorption?

Cotton dipped in ink

The correct answer is option 2. Cotton dipped in ink.

Let us break down why "Cotton dipped in ink" is an example of sorption:

Absorption: When cotton is dipped in ink, the ink is drawn into the small spaces within the cotton fibers. This process is known as absorption, where one substance (the absorbent, which is cotton in this case) takes in another substance (the absorbate, which is ink) into its internal structure. The ink becomes dispersed throughout the cotton fibers rather than just sticking to the surface.

Adsorption: Additionally, some of the ink molecules may adhere to the surface of the cotton fibers. This surface attachment of ink molecules to the cotton fibers is an example of adsorption. The ink molecules are held onto the surface of the cotton fibers by intermolecular forces.

Combining absorption and adsorption, the overall process of ink being taken up by the cotton fibers involves both absorption into the internal structure of the cotton and adsorption onto the surface of the cotton. This combined process is referred to as sorption. Therefore, "Cotton dipped in ink" exemplifies sorption.