Question

The diameter range of colloidal particles is approximately

• A. \(1\) to \(1000\ \mathrm{nm}\)
• B. \(1000\) to \(2000\ \mathrm{nm}\)
• C. \(2000\) to \(3000\ \mathrm{nm}\)
• D. \(3000\) to \(4000\ \mathrm{nm}\)

Hint:

Particle size ranges: True solution \(\lt 1\ \mathrm{nm}\), Colloid \(1-1000\ \mathrm{nm}\), Suspension \(\gt 1000\ \mathrm{nm}\).

Answer 1

The Correct Option is A

Step 1: Understand what a colloid is.
A colloid is a heterogeneous system in which one substance is dispersed uniformly in another substance.
The particles in a colloid are larger than particles in a true solution but smaller than particles in a suspension.

Step 2: Recall the size range of true solution particles.
In a true solution, the particle size is less than
\[ 1\ \mathrm{nm} \]
These particles are too small to scatter light.

Step 3: Recall the size range of suspension particles.
In suspensions, the particle size is greater than
\[ 1000\ \mathrm{nm} \]
These particles are large enough to settle down on standing.

Step 4: Determine the colloidal range.
Since colloidal particles lie between true solution particles and suspension particles, their size range is approximately
\[ 1\ \mathrm{nm}\ \text{to}\ 1000\ \mathrm{nm} \]

Step 5: Compare with the given options.
Option (1) exactly matches the standard size range of colloidal particles.
The other options represent sizes larger than the colloidal range and belong more to suspensions.

Step 6: Final conclusion.
Hence, the approximate diameter range of colloidal particles is
\[ \boxed{1\ \text{to}\ 1000\ \mathrm{nm}} \]

Step 7: Additional concept.
Because of this intermediate size range, colloidal particles show special properties such as:
Tyndall effect and
Brownian motion