Question

Which of the following solution(s) shows Tyndall effect ?

• A. Salt solution
• B. Milk
• C. $CuS{O}_4$ solution
• D. Starch solution

Answer 1

Answer: (B), (D)

Starch solution

Tyndall effect:
If a strong beam of ​light is passed​ through a colloidal sols placed in dark place,​ path of the beam ​gets illuminated. This effect is called Tyndall effect.
This effect was first observed ​by faraday later studied in ​detail by Tyndall​.
This effect arises due to scattering of light by colloidal​ particles in all directions . Thus, scattering of light illuminates the path of beam in the colloidal dispersion​.

It is used to distinguish between ​a colloidal and a true solution​.
True solution does not show Tyndall effect but colloidal solution shows​.

Salt solution and $CuS{O}_4$ solutions are true solutions so they do not show Tyndall effect whereas milk and starch are colloidal solutions so they shows Tyndall effect.
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