Question

During an experiment the students prepared three mixtures A)Starch in water B) Sodium
chloride solution C) Tincture of Iodine.
i) Students observed a visible beam of light through mixture A. Why?
ii) Tincture of Iodine did not show Tyndall effect . Explain reason.
iii) How can you relate particle size to Tyndall effect?

Answer 1

Tyndall effect refers to the scattering of light in a solution. Tyndall effect occurs when the size of particles in the solution exceeds 1 nm in diameter. Such solutions are actually called false solutions.

In tincture of iodine, the size of particles in solution is less than 1 nm in diameter hence the solution does not exhibit Tyndall effect. Hence, tincture of iodine is a true solution.

Therefore, if the size of particles in solution exceeded 1nm in diameter, Tyndall effect is observed.

Hope this will help you :)