In the context of solutions and mixtures, which statement best describes the difference between a colloid and a true solution?

• A. A colloid contains dispersed particles large enough to scatter light (Tyndall effect), whereas a true solution has solute particles at the molecular/ionic scale that do not scatter light appreciably.
• B. In a true solution the solute particles are larger than in a colloid, which is why solutions appear cloudy.
• C. A true solution can be separated by filtration, whereas a colloid cannot be separated by filtration.
• D. A colloid is always a pure substance, whereas a true solution is always a heterogeneous mixture.

Answer: (A)