Final answer:
The correct answer is option 1. Colloids differ from suspensions in several ways. Colloids do not settle out upon standing, have smaller particles, can be separated by a semipermeable membrane, and can be transparent or opaque. Suspensions, on the other hand, settle out on standing, have larger particles, cannot be filtered, and are usually opaque.
Step-by-step explanation:
A suspension is a heterogeneous mixture of particles distributed throughout a second phase, while a colloid is a heterogeneous mixture whose particle size is intermediate between a solution and a suspension.
In suspensions, the dispersed particles settle out upon standing, while in colloids, the dispersed particles do not settle out. Colloids can be classified as sols, gels, aerosols, or emulsions, depending on the nature of the dispersed phase and the dispersion medium.
Colloids can be distinguished from suspensions by their ability to scatter light, known as the Tyndall effect.
The dispersed particles in colloids are generally smaller than those in suspensions, ranging from 2 to about 500 nm in diameter. Additionally, colloids can be separated by a semipermeable membrane, while suspensions cannot be filtered. Finally, while colloids can be transparent or opaque, suspensions are usually opaque.