Question

Chalk powder in water is an example of:

• A. Saturated solution
• B. Unsaturated solution
• C. Suspension
• D. Colloidal solution

Hint:

Suspensions are mixtures where the solute particles are large enough to settle out of the solvent over time.

Answer 1

The Correct Option is C

To understand why chalk powder in water is an example of a suspension, let's explore the characteristics of a suspension and compare it to other solution types:

• Saturated Solution: This is a solution in which no more solute can dissolve at a given temperature. Typically, it involves clear solutions where the solute is fully integrated into the solvent.
• Unsaturated Solution: This type of solution can still dissolve more solute at the given temperature. Like saturated solutions, unsaturated solutions appear homogenous and clear.
• Suspension: A suspension is a heterogeneous mixture in which the solute particles do not dissolve but remain dispersed throughout the bulk of the solvent. The particles are visible to the naked eye, and they tend to settle down upon standing. Chalk powder in water fits this definition as the chalk particles are large enough to be seen and will settle over time.
• Colloidal Solution: This is a mixture where very small particles of one substance are evenly distributed throughout another. The particles in a colloid are smaller than those in a suspension but larger than those in a true solution. They do not settle out under the influence of gravity.

Based on these definitions, chalk powder in water forms a suspension because:

• The chalk particles are large and do not dissolve in water.
• The mixture is heterogeneous, meaning distinct visible particles exist.
• Given time, the particles of chalk will settle to the bottom of the container, separating from the water.

Answer 2

Chalk powder stirred into water is being classified here. Judge each option by what actually happens physically when chalk is mixed with water.

1. Saturated solution: a saturated solution needs the solute to dissolve completely up to its limit. Chalk powder does not dissolve in water at all, so this cannot be it.
2. Unsaturated solution: this also requires the solute to dissolve, just below the limit. Since chalk does not dissolve, this is ruled out too.
3. Suspension: chalk particles are visible, do not dissolve, and settle to the bottom of the container after the water is left standing. That is exactly what happens with chalk powder in water.
4. Colloidal solution: colloidal particles stay dispersed and do not settle out on standing, but chalk powder clearly settles, so this does not fit.

Since chalk powder does not dissolve and settles out over time, the mixture is a suspension.

So the correct answer is suspension.