What are examples of fine dispersions?

• A. Magmas/Gels
• B. Emulsions
• C. Solutions
• D. Suspensions

Answer: (A)

Fine dispersions are colloidal systems in which the dispersed phase is distributed in a continuous phase as extremely small particles. This tiny size keeps the particles suspended and gives properties between true solutions and coarse suspensions. Magmas are suspensions of finely divided solids in a liquid vehicle that is thick enough to keep the particles dispersed, making them a classic example of a colloidal dispersion. Gels are networks that trap liquid within a solid-like matrix, forming a colloidal system where the dispersed liquid is held in a three-dimensional network. Both magmas and gels fit the colloidal (fine dispersion) category. Emulsions involve droplets of one liquid dispersed in another immiscible liquid and are a related colloidal system but are considered a distinct class in many pharmaceutics contexts; solutions are true molecular dispersions with no discrete particles, so they are not dispersions, and suspensions are typically coarse dispersions with larger particles that settle more readily. Therefore magmas and gels are the exemplified fine dispersions.