Which of the following solution is a colloid: September 2007
**Core Concept**
A colloid is a mixture in which one substance of microscopically dispersed insoluble particles is distributed throughout another substance. In medical and pharmaceutical contexts, colloids are used as volume expanders, plasma substitutes, and in wound dressings.
**Why the Correct Answer is Right**
The correct answer is a colloid because it contains particles that are larger than those in a true solution but smaller than those in a suspension. The particles in a colloid are dispersed throughout the solution and remain suspended, rather than settling out. This property makes colloids useful for medical applications where a rapid increase in blood volume is needed. For example, gelatin-based colloids can be used to treat hypovolemic shock.
**Why Each Wrong Option is Incorrect**
**Option A:** Not a colloid, as it is a true solution where the particles are fully dissolved and evenly distributed throughout the solvent.
**Option B:** Not a colloid, as it is a suspension where the particles are larger and settle out over time.
**Option C:** Not a colloid, as it is a mixture of two or more liquids that are not chemically combined.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that colloids are not the same as true solutions or suspensions, and their unique properties make them useful in specific medical applications.
**Correct Answer:** C.