when we add 1-2 drops of rice in 100ml water ,what do we get a colloid or suspension
The correct answer and explanation is:
When we add 1–2 drops of rice (or more precisely, small rice particles) into 100 mL of water, we form a suspension, not a colloid.
🔍 Explanation (300 words):
To understand this, let’s first review the differences between suspensions, colloids, and true solutions, based on particle size and behavior:
| Type | Particle Size | Appearance | Settling Behavior | Tyndall Effect |
|---|---|---|---|---|
| Solution | < 1 nm | Transparent | Does not settle | No |
| Colloid | 1–1000 nm (1 µm) | Cloudy, translucent | Does not settle easily | Yes |
| Suspension | > 1000 nm (1 µm) | Opaque or cloudy | Particles settle | Yes |
When rice (solid) is added to water (liquid), even if it’s just 1–2 drops (which might contain only a few grains), the rice particles are still relatively large—much larger than the colloidal size range. Rice does not dissolve in water, nor does it break into fine colloidal particles simply by being added. Instead, the rice remains visible and, after a short time, settles to the bottom of the container due to gravity.
This behavior is characteristic of a suspension:
- Heterogeneous mixture (you can see the rice separately).
- Particles are large and settle upon standing.
- Can be separated by filtration or decantation.
In contrast, colloids (like milk or gelatin) have much finer particles that remain evenly dispersed and do not settle out easily.
So, adding a small amount of rice to water—even in tiny amounts—does not form a colloid. The size and weight of rice particles are simply too large and dense. It forms a temporary suspension that eventually separates.
✅ Conclusion:
Adding rice to water forms a suspension, because the rice particles are large, visible, and settle out over time.