Question

Three students A, B, and C prepared mixtures using chalk powder, common salt, and milk respectively in water. Whose mixture:
      (A) Would not leave residue on filter paper after filtration?
      (B) Would show Tyndall effect?
      (C) Would give a transparent solution?
      (D) Would it show stability?

Answer 1

Hint: A homogenous mixture has the same uniform appearance and composition throughout. Heterogeneous solutions consist of visible different substances or phases. The three phases or states of matter are gas, liquid and solid. Colloids are a type of homogenous solution with intermediate particle size between solution and a suspension.

Complete solution:
The solubility of a substance is its maximum amount that can be dissolved in a specified amount of solvent at specific temperature. It depends on the nature of solvent and solute as well as temperature and pressure. Every solid cannot dissolve completely in solid; it depends on the type of solid. Milk is a liquid in liquid type of solution. In the case of chalk powder there is less dissolved solution. Because its solubility is less than others.
(A)Student mixture B and C would not leave residue on filter paper after mixture. Because of the high solubility of common salt and milk in water. Common salt mixture is a type of homogenous solutions, milk is a type of colloidal solution and chalk powder mixture is a type of heterogeneous mixture.
(B) The Tyndall effect is light scattering solid particles are suspended in a liquid. The student mixture is only visible by Tyndall effect because of the solubility of chalk powder in water very less which forms a suspension solution. This type of solution is colloidal which is a type of homogenous solution with intermediate particle size between solution and a suspension.
(C) Student mixture B will give a transparent solution because milk is fully dissolved in water.
(D) Student mixture B and C are more stable in water. Common salt and milk highly soluble solute in water. Hence, if the solubility is more, then the mixture will be more stable.

Note:
The easy explanation that the concentration of solute either chalk powder, milk or common salt is much important. Because concentration of the solution depends on solute. If solid sparingly soluble until saturated, after that it does not dissolve rather form precipitation.