Question

Tyndall effect is observed when light passes through:

• A. Copper sulphate solution
• B. Sodium chloride solution
• C. Water
• D. Starch solution

Answer 1

The correct option is D

Starch solution

Tyndall effect:

• The phenomenon in which the solute particles of a colloid scatter the beam of light and show its path is called the Tyndall effect.
• The colloidal solution has the property of the Tyndall effect.
• For example, a starch solution which is also a colloid shows the Tyndall effect.

The explanation for the correct answer:

Option D: Starch solution

• Colloidal solution has the property of the Tyndall effect.
• Starch solution is also a colloid so it shows the Tyndall effect.

• So, option D is the right answer.

The explanations for the incorrect answers:

Option A:$\mathrm{Copper}\mathrm{sulphate}\left({\mathrm{CuSO}}_4\right)$ solution

• Due to the small size of particles of solute in $\mathrm{Copper}\mathrm{sulphate}\left({\mathrm{CuSO}}_4\right)$ solution it is not able to scatter a beam of light passing through the solution.
• Hence it does not show the Tyndall effect.
• So, option A is the wrong answer.

Option B: $\mathrm{Sodium}\mathrm{chloride}\left(\mathrm{NaCl}\right)$ solution

• Due to the small size of particles of solute in $\mathrm{Sodium}\mathrm{chloride}\left(\mathrm{NaCl}\right)$ solution it is not able to scatter a beam of light passing through the solution.
• Hence it does not show the Tyndall effect.
• So, option B is the wrong answer.

Option C: Water$\left({\mathrm{H}}_2\mathrm{O}\right)$

• Water is a pure solvent, and it does not have solute particles to scatter the light so it will not show the Tyndall effect.
• So, option C is the wrong answer.

Conclusion:

So, the Tyndall effect is observed when light passes through the starch solution.

Therefore, the right answer is option D.