Question

A true solution does not show Tyndall effect, because of the:

• A. Nature of solvent
• B. Amount of solute
• C. Size of the particles
• D. Nature of solute

Hint:

The Tyndall effect is observed when light is scattered by larger particles (colloidal particles) in a medium, not by small particles in a true solution.

Answer 1

The Correct Option is C

A true solution does not display the Tyndall effect because of the size of its particles. The Tyndall effect is a phenomenon where light is scattered by particles in a colloid or in fine suspension. True solutions, such as salt in water or sugar in water, consist of solute particles that are ions or molecules of very small size, typically less than 1 nanometer (nm) in diameter. These particles are too small to scatter visible light; therefore, light passes through the solution without being scattered, making the solution appear clear.

• Nature of solvent: The solvent's nature does not specifically affect the Tyndall effect in a true solution.
• Amount of solute: The concentration does not typically influence whether the Tyndall effect occurs; instead, it's the size of the particles.
• Size of the particles: Correct choice. True solutions have particles so small that they do not scatter light.
• Nature of solute: Similar to solvent, the nature of solute does not influence the Tyndall effect in true solutions on its own. It's the particle size that is crucial.

Answer 2

The Tyndall effect happens when particles in a mixture are large enough to scatter a beam of light passing through it. Whether a mixture shows this effect comes down to how big its dispersed particles are. Let's weigh each option on that basis.

1. Nature of solvent: Changing the solvent (water, alcohol, and so on) does not change whether the dissolved particles are big enough to scatter light, so the solvent's identity is not the deciding factor here.
2. Amount of solute: Adding more or less solute changes how many small particles are present, but if those particles are already too small to scatter light individually, adding more of them still will not produce the Tyndall effect.
3. Size of the particles: True solutions have solute particles below about 1 nanometre, ions or single molecules, far too small to scatter visible light, so light passes straight through without a visible beam path. This is exactly why the Tyndall effect is absent.
4. Nature of solute: Whether the solute is a salt, a sugar, or an acid does not matter for scattering; what matters is that in a true solution, whatever the solute is, its particles are broken down to molecular or ionic size.

Because the dissolved particles in a true solution are far smaller than the wavelength of visible light, they cannot scatter it, so no Tyndall effect is seen.

So the correct answer is size of the particles.