Answer :
Answer:
In the context of biology and chemistry, let's differentiate between true solutions, colloidal solutions, and suspensions:
1. **True Solution:**
- **Definition:** A true solution is a homogeneous mixture of two or more substances where the solute particles are very small (typically less than 1 nanometer in diameter) and do not settle down.
- **Characteristics:**
- The solute particles are molecular or ionic in nature.
- They do not scatter light and are not visible under a microscope.
- The solute particles cannot be separated from the solvent by filtration.
- Example: Salt dissolved in water, sugar dissolved in water.
2. **Colloidal Solution (Colloid):**
- **Definition:** A colloidal solution is a heterogeneous mixture where the particle size of the dispersed phase (solute) is intermediate between those found in true solutions and suspensions.
- **Characteristics:**
- The solute particles are larger than those in true solutions but smaller than those in suspensions (typically between 1 nanometer to 1000 nanometers).
- They scatter light and are usually cloudy or milky in appearance.
- They do not settle down on standing but may undergo Brownian motion.
- Colloids can be separated from a mixture by ultrafiltration.
- Example: Milk, blood, gelatin, aerosols.
3. **Suspension:**
- **Definition:** A suspension is a heterogeneous mixture where the solute particles are much larger than those found in colloids or true solutions.
- **Characteristics:**
- The solute particles are visible to the naked eye and can settle down when left undisturbed.
- They scatter light and appear cloudy.
- The solute particles can be separated from the solvent by filtration.
- Example: Muddy water, chalk-water mixture, sand in water.
**Summary:**
- **True Solution:** Homogeneous mixture, solute particles are molecular or ionic, cannot be seen under a microscope, do not settle, and cannot be separated by filtration.
- **Colloidal Solution:** Heterogeneous mixture, solute particles are larger than in true solutions but smaller than in suspensions, scatter light, do not settle, and can be separated by ultrafiltration.
- **Suspension:** Heterogeneous mixture, solute particles are visible to the naked eye, settle over time, scatter light, and can be separated by filtration.
Understanding these differences helps in identifying and categorizing various types of solutions based on the size of solute particles and their behavior in the solvent.