The correct option is (c).
Explanation
A true solution is a homogeneous mixture of two or more substances. In a solution, the solute particles are dissolved at the molecular or ionic level within the solvent, resulting in specific physical properties distinct from colloids and suspensions.
Statement-wise Analysis:
- Statement 1 is Incorrect. The particles in a true solution are extremely small, typically less than 1 nanometer ($10^{-9}$ meters) in diameter. Due to this minute size, they cannot be seen with the naked eye or even through a powerful microscope.
- Statement 2 is Correct. A true solution is stable. The solute particles are uniformly distributed and do not settle down when left undisturbed, unlike particles in a suspension.
- Statement 3 is Correct. Because the particles in a true solution are so small, they do not scatter a beam of light passing through the solution. Consequently, the path of light is not visible inside the solution (absence of the Tyndall effect).
Key Takeaway:
True solutions are characterized by homogeneity, extremely small particle size (<1 nm), stability (do not settle), and the inability to scatter light (no Tyndall effect).