You are here
๐ฌ Think about it
Blood can be spun apart like a suspension, yet its cells are too small to see, like a solution. So which is it? Neither — it is something in between, called a colloid. Let us understand colloids.
What is a colloid?
- It is a mixture that is neither a true solution nor a true suspension.
- Its particles are bigger than in a solution but smaller than in a suspension.
- The particles do not settle over time.
- They stay uniformly spread, as in a solution.
Example:
Blood, milk, tomato sauce and ice cream are colloids.
How do solutions, colloids and suspensions differ in particle size?
- A solution has the smallest particles (less than 1 nm).
- A colloid has medium particles (1–1000 nm).
- A suspension has the largest particles (more than 1000 nm).
| Mixture | Particle size | Do particles settle? |
|---|---|---|
| Solution | Less than 1 nm | No |
| Colloid | 1–1000 nm | No |
| Suspension | More than 1000 nm | Yes |
Important Points
- A colloid sits between a solution and a suspension.
- Its particles do not settle and stay evenly spread.
- Particle size: solution < colloid < suspension.
๐ Bridging Science and Society
- Donating blood saves lives in emergencies and surgeries.
- Donated blood is tested and separated into components like plasma and cells.
- These are stored in blood banks and supplied when needed.
- The body naturally replaces donated blood within a few weeks.
โ Test Yourself
-
Is blood a solution, suspension or colloid?
View Answer
A colloid. -
Which mixture has the largest particles?
View Answer
A suspension (more than 1000 nm). -
Do colloid particles settle over time?
View Answer
No — they stay evenly spread out.
Important Definitions
- Colloid — a mixture whose particle size is between that of a solution and a suspension, and whose particles do not settle.
๐ NCERT Question 10 — Blood is an example
Blood is a colloid — what if it behaved like a suspension, and name its dispersed phase and medium.
View Answer →
๐ NCERT Question 3 — A mixture can be
Sort the given properties and examples into solution, suspension and colloid (Table 5.2).
View Answer →
