Which of the following statements are true?

A. Flocculation value is inversely proportional to the coagulating power.

B. Colloidal silicon is a protective colloid

C. Alum is used for cleaning muddy water

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

Choose the appropriate answer from the options given below:

A, B, C, D only

The correct answer is option 4. A, B, C, D only.

Let us break down each statement:

A. Flocculation value is inversely proportional to the coagulating power.

Flocculation value refers to the concentration of a substance needed to cause flocculation (clumping) of suspended particles in a liquid. Higher flocculation value means more of the substance is required to cause flocculation, indicating lower coagulating power because it takes more substance to cause particles to come together.

B. Colloidal silicon is a protective colloid.

A protective colloid is a substance that, when added to a colloidal solution, prevents the precipitation or coagulation of the dispersed phase. Colloidal silicon can act as a protective colloid, meaning it helps to stabilize colloidal suspensions by preventing the particles from aggregating or settling.

C. Alum is used for cleaning muddy water.

Alum, or aluminum sulfate, is commonly used in water treatment processes to clarify muddy water. When added to water, alum forms a gelatinous precipitate called floc, which traps suspended particles, impurities, and colloids, making them easier to remove by settling or filtration.

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

Gelatin is often added to ice cream primarily as a stabilizer and thickening agent. While it can aid in emulsification to some extent, its main role in ice cream is to improve texture and mouthfeel by forming a gel-like structure that helps hold air bubbles and prevents ice crystals from forming, rather than acting primarily as an emulsifier.

So, statements A, B, C, and D are all true.