The correct answer is D. Dialysis.
Colloids are a mixture of two or more substances where one substance is dispersed in another substance in the form of very small particles. The dispersed substance is called the dispersed phase, and the substance in which it is dispersed is called the dispersion medium. The particles of the dispersed phase are too small to be seen with the naked eye, but they are large enough to scatter light. This is why colloids are often called “colloidal suspensions.”
Colloids can be purified by a variety of methods, including dialysis. Dialysis is a process that uses a semipermeable membrane to separate dissolved substances from a solution. The membrane allows certain molecules to pass through, while others are blocked. This allows the colloid to be purified by removing any unwanted substances that are dissolved in it.
The other options are incorrect because they are not methods of purifying colloids.
- Condensation is a process that occurs when a gas changes into a liquid. This process does not involve the separation of substances, so it cannot be used to purify colloids.
- Centrifugation is a process that uses centrifugal force to separate substances. This process can be used to purify colloids, but it is not as effective as dialysis.
- Filtration is a process that uses a filter to separate substances. This process can be used to purify colloids, but it is not as effective as dialysis.