Question

Which of the following involves coagulation?

• A. Formation of rubber from latex.
• B. Curdling of milk.
• C. Creaming of milk.
• D. Precipitation of carbon from smoke.

Answer 1

Answer: (A), (B), (D)

The correct options are
A Formation of rubber from latex.
B Curdling of milk.
D Precipitation of carbon from smoke.

For water purification processes, alum acts as a coagulant. A coagulant binds extremely fine and small particles suspended in raw impure water into larger particles that can be removed by filtration and settling. Creaming of milk is not an example of coagulation.
This allows for the removal of unwanted color and cloudiness (turbidity). Butter is a water-in-oil emulsion made from 'cream by phase inversion' (milk as an oil-in-water emulsion, is discussed further on).