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

Compare chalk powder in water with sand stirred into a glass of water. Shake the glass and the sand swirls around cloudily, then within a minute or two it sinks to the bottom, leaving the water mostly clear again.

1. Saturated solution: that would need the chalk to fully dissolve first, the way salt dissolves in water, which chalk does not do.
2. Unsaturated solution: same problem, chalk is not dissolving into the water at any level, so this label does not apply.
3. Suspension: the sand-in-water comparison matches chalk powder closely: visible particles, no dissolving, and settling after standing.
4. Colloidal solution: milk is the usual comparison for a colloid, and milk does not separate into layers the way chalk-water does on standing, so chalk-water does not belong here.

Since chalk powder in water behaves like the sand example, settling out rather than dissolving or staying dispersed, the correct answer is suspension.

Answer 2

Use one clear test to sort the options: does the substance dissolve, and if not, does it stay dispersed or does it settle out?

1. Saturated solution: requires the solute to be fully dissolved. Chalk fails this test immediately since it does not dissolve in water.
2. Unsaturated solution: also requires dissolving, just not yet at the limit. Chalk fails the same test.
3. Suspension: chalk does not dissolve, its particles are large enough to see, and it settles under gravity given time. It passes every part of this test.
4. Colloidal solution: would require the particles to stay dispersed without settling, but chalk particles do settle, so this fails the last part of the test.

Chalk powder in water fails the dissolving test and passes the settling test, which is the exact signature of a suspension, so that is the correct answer.