Given below are two statements:
Statement I : Emulsions of oil in water are unstable and sometimes they separate into two layers on standing.
Statement II : For stabilisation of an emulsion, excess of electrolyte is added.
In the light of the above statements, choose the most appropriate answer from the options given below :

We need to evaluate two statements about emulsions.

Statement I: "Emulsions of oil in water are unstable and sometimes they separate into two layers on standing."

This statement is correct. Emulsions are thermodynamically unstable systems. Without an emulsifying agent (stabilizer), oil-in-water emulsions tend to separate into two distinct layers over time due to the tendency to minimize the interfacial area between the two immiscible liquids. This process is called demulsification or creaming.

Statement II: "For stabilisation of an emulsion, excess of electrolyte is added."

This statement is incorrect. Emulsions are stabilized by adding emulsifying agents (also called surfactants or emulsifiers) such as soaps, detergents, proteins (like casein), or gums. These substances form a protective layer around the dispersed droplets, preventing coalescence.

In fact, adding excess electrolyte to an emulsion can actually destabilize it by compressing the electrical double layer around the dispersed droplets (similar to coagulation of colloids). This is the opposite of stabilization.

Therefore, Statement I is correct but Statement II is incorrect.

The correct answer is Option C.