Solutions and Solubility
Subject: Science (Chemistry) | Topic: Solutions and Solubility
For TLT, ECT, PST, JEST & All Competitive Exams
In our last topic, we studied the States of Matter — Solid, Liquid, and Gas. When substances mix together, especially in the liquid state, they often form a Solution. Understanding how substances dissolve is a core, frequently tested area of Chemistry in TLT, ECT, PST, and JEST exams.
What is a Solution?
A Solution is a homogeneous mixture of two or more substances, where one substance is completely and evenly dissolved in another. A solution has two main components:
- Solute: The substance that gets dissolved (present in a smaller amount). Example: Salt or sugar.
- Solvent: The substance that does the dissolving (present in a larger amount). Example: Water.
Types of Solutions (Based on Saturation)
| Type | Description |
|---|---|
| Saturated Solution | Contains the maximum amount of solute that can dissolve at a given temperature |
| Unsaturated Solution | Contains less solute than the maximum amount that could dissolve |
| Supersaturated Solution | Contains more dissolved solute than normally possible at that temperature (unstable) |
Solute Dissolving in a Solvent
Factors Affecting Solubility
Solubility is the maximum amount of solute that can dissolve in a given amount of solvent at a specific temperature. It depends on:
| Factor | Effect |
|---|---|
| Temperature | Solubility of most solids increases as temperature increases |
| Nature of Solute and Solvent | "Like dissolves like" — polar solutes dissolve in polar solvents |
| Pressure | Affects mainly the solubility of gases (higher pressure increases gas solubility) |
| Stirring/Agitation | Speeds up the rate of dissolving but does not increase the total amount dissolved |
Types of Mixtures
| Type | Example | Nature |
|---|---|---|
| Solution | Salt water | Homogeneous (uniform throughout) |
| Suspension | Muddy water | Heterogeneous; particles settle over time |
| Colloid | Milk | Particles are spread but do not settle; scatters light |
Why This Topic Matters
Solutions and Solubility connect directly to earlier topics like States of Matter and Acids, Bases and Salts, since acids and bases are often studied as aqueous solutions. This practical, everyday topic is a reliable, frequently tested area in TLT, ECT, PST, and JEST exams.
Practice MCQs
1. In a sugar-water solution, which substance is the solute?
a) Water b) Sugar c) Both equally d) Neither
2. Why is water called the "Universal Solvent"?
a) It dissolves nothing b) It can dissolve more substances than any other liquid c) It is always a solute d) It never mixes with anything
3. A solution that contains the maximum solute that can dissolve at a given temperature is called:
a) Unsaturated b) Saturated c) Diluted d) Colloidal
4. Which factor increases the solubility of most solids?
a) Decreasing temperature b) Increasing temperature c) Removing the solvent d) Freezing
5. Which of the following is an example of a colloid?
a) Salt water b) Sugar water c) Milk d) Air
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