What is a colloid?

A colloid is defined as a mixture in which small particles are dispersed throughout a continuous medium without settling out over time. The particles in a colloid are larger than those found in a true solution but are still small enough to remain suspended; typically, their size ranges from about 1 nanometer to 1 micrometer. This is why option B accurately describes a colloid as "a solution with larger particle size that does not settle out."

The nature of colloids is such that they exhibit properties distinct from true solutions and suspensions. In a true solution, particles are at the molecular or ionic level and do not scatter light (tyndall effect), while in suspensions, larger particles can settle out when left undisturbed over time. Colloids, however, do not settle out due to the kinetic energy of the particles and also can scatter light, making them appear cloudy.

The other provided options do not accurately represent the characteristics of a colloid. A colloid is not limited to a mixture of gases; it can involve liquid, solid, and gas components. While a colloid can appear to be a solution, it does not qualify as a truly ‘filtered’ solution since the particles are too small to be easily removed