Question

Pick out the colloid from the following:

Salt solution, sugar solution, muddy water, milk.

Answer 1

1. Colloid: A colloidal solution is a solution in which the size of the solute particles is intermediate between those in true solutions and suspension. Example: milk.
2. A homogenous mixture is a mixture in which the particles of solute are spread uniformly throughout the solvent. Example: sugar solution (sugar dissolved in water).
3. Suspension is a heterogeneous mixture in which the solute particles do not dissolve but remain suspended together throughout the bulk of the solvent. Example: smoke in the air.

Classifying the given substances:

1. Salt solution and sugar solutions are homogenous mixtures as in these mixtures the particle of salt and sugar are evenly spread throughout water.
2. Muddy water is an example of a suspension because the particles of mud after leaving the solution untouched for sometime, get settled down at the bottom of the container.
3. Milk is a colloid because the it contains particles that remain suspended in the liquid and their size is intermediate to the size of true solution and suspension.

Hence, out of all the given options, milk is the colloid.