Question

When Ben Franklin took a spoonful of olive oil and dropped onto the surface of a pond, he basically observed an oil slick. Explain the structure or organization of this oil in the oil slick. Explain how continuing to add oil to the pond would eventually form oil droplets.

Answer 1

When we add a spoonful of olive oil and dropped onto the surface of a pond, an oil slick is observed.

As if we mix two liquids density is a factor that plays a important role in their mixing, as water is more dense than oil will place on the top of water. Also oil and water does not mix with each other as they are Hydrophobic in nature because of their non-polar molecular structure or partially localized charge.

Formation of oil droplets on further adding oil to the water can be explained on the basis of surface tension and intermolecular forces.

When we add small amount of oil then adhesive force between water and oil is greator than the cohesive force between the oil molecules.

Adding of oil to water results in decrease the surface tension of water( between the intermixing layer of two liquids) and on increasing amount of oil cohesive force between oil molecules becomes comperable to adhesive force results in the increase in the surface tension on layer(between oil and air) this results in the formation of oil droplets on contuning add oil.

Cohesive force- Force acting in between similar kind of molecules.

Adhesive force- Force acting in between the different kind of molecules of two different species.