Which of the following statements are true?

A. The coagulation of lyophobic sols can be done by electrophoresis.

B. Principal emulsifying agent for W/O emulsions ate proteins, soaps, gums etc.

C. Alum is used for cleaning muddy water.

D. Gelatin is added in ice cream to act as emulsifier.

Choose the correct answer from the options given below:

C, A and D only

The correct answer is option 3. C, A and D only.

Let us go through each statement again in detail to understand why the correct answer is option 3: C, A, and D only.

Statement Analysis:

A. The coagulation of lyophobic sols can be done by electrophoresis.

This statement is true. Electrophoresis is a process where colloidal particles are moved towards oppositely charged electrodes, discharged, and precipitated. This is a common method to coagulate lyophobic sols.

B. Principal emulsifying agents for W/O emulsions are proteins, soaps, gums, etc.

Water-in-oil (W/O) emulsions require emulsifiers that stabilize the water droplets in the oil phase. Proteins and gums are effective emulsifiers for W/O emulsions. Soaps, on the other hand, are more commonly used as emulsifiers in oil-in-water (O/W) emulsions due to their amphiphilic nature which favors water dispersion.

Conclusion: The statement is partially true. Proteins and gums are correct, but soaps are typically used for O/W emulsions rather than W/O emulsions.

C. Alum is used for cleaning muddy water.

Alum (potassium alum) is widely used in water treatment to clarify muddy water. It acts as a coagulant by causing the suspended particles to clump together and form larger aggregates (flocs), which can then be removed more easily.

Conclusion: This statement is true. Alum is a well-known agent for cleaning and clarifying water.

D. Gelatin is added in ice cream to act as an emulsifier.

Gelatin is used in ice cream primarily to improve texture and prevent the formation of large ice crystals. It stabilizes the ice cream mixture, which helps in maintaining a smooth texture. While gelatin does have emulsifying properties to some extent, its main role in ice cream is to stabilize the texture and prevent ice crystallization.

Conclusion: This statement is true. Gelatin helps in stabilizing the texture of ice cream, which indirectly affects emulsification and consistency.

Given the evaluation, the correct answer that includes the accurate statements about alum and gelatin, and the somewhat acceptable statement about electrophoresis, is option 3: C, A, and D only.