Question

Which of the following systems will show Tyndall effect?
(A) Aqueous solution of sodium chloride
(B) Aqueous solution of aluminum hydroxide
(C) Aqueous solution of glucose
(D) Aqueous solution of area

Answer 1

Hint: When a beam of light passed through a medium containing small suspended particles, it scatters and this phenomenon is called Tyndall Effect
Example: smoke, dust, scatter particles.

Complete step by step answer:
Now first we discuss the conditions required for Tyndall effect.
Tyndall effect only shown by colloidal solution or in a very few suspensions.
This effect is used to verify if a given solution is a colloid.
In the given example aqueous solution of sodium chloride, glucose and area are true solutions. Particle size in solution is very small.
Therefore, they do not show Tyndall effect.
Aqueous solution of $Al{(OH)_3}$ is $\alpha $ colloidal solution therefore it shows Tyndall effect.
Therefore, from the above explanation the correct option is Aqueous solution of aluminum hydroxide.
When a beam of light passes through a colloid, the colloidal particles in solution do not allow the beam to completely pass through.
They scatter the light.
Thus scattering makes the path of the light beam visible.

Colloidal particle size should range from $40$ to $900$ nanometers [$1$nanometer$ = {10^{ - 9}}$meter].

So, the correct answer is “Option B”.

Additional Information:
Solutions are classified into three types on the basis of particle size.
(1) True solution: This homogenous mixture. The particle size is less than ${10^{ - 9}}m$ or $1nm.$
Example:
Solutions of $NaCl,$ glucose, are a true solution.
(2) Colloidal solution: This is heterogeneous mixture and particle size is about $1nm.$
Example:
Blood, ink, starch is a colloidal solution.
(3) Suspension: This is Heterogeneous mixture containing a large number of particles.
Sand in water is an example of suspension.

Note:
True solution mixture thoroughly together because the particles of solid are very fine.
Colloidal solutions are colloids suspension intermediate between true solution and suspension.
Suspension doesn’t mixture together entirely. They settle at the bottom.