Statement I: For colloidal particles, the values of colligative properties are of small order as compared to values shown by true solutions at same concentration.
Statement II: For colloidal particles, the potential difference between the fixed layer and the diffused layer of same charges is called the electrokinetic potential or zeta potential.
In the light of the above statements, choose the correct answer from the options given below:

We need to evaluate both statements about colloidal particles and determine their truth values. For colloidal particles, the values of colligative properties are of small order as compared to values shown by true solutions at the same concentration. This is TRUE. Colligative properties (such as osmotic pressure, boiling point elevation, freezing point depression, and relative lowering of vapour pressure) depend on the number of solute particles in solution, not on their nature or size. The key formula for osmotic pressure, for example, is:

where $$n$$ is the number of moles of solute particles. In a colloidal solution, each colloidal particle is actually an aggregate of many individual molecules or ions. Therefore, at the same mass concentration, a colloidal solution has far fewer particles than a true solution. Since fewer particles means smaller colligative effects, colloidal solutions show much smaller values of colligative properties compared to true solutions at the same concentration.

For colloidal particles, the potential difference between the fixed layer and the diffused layer of same charges is called the electrokinetic potential or zeta potential. This is TRUE. In a colloidal system, each colloidal particle carries an electric charge. This charge attracts counter-ions from the surrounding medium, forming what is known as the electrical double layer:
Fixed layer (Stern layer): A layer of ions firmly attached to the surface of the colloidal particle.
Diffused layer: A layer of ions that are loosely associated and extend into the bulk of the solution.
The potential difference between the fixed (Stern) layer and the diffused layer is called the zeta potential (or electrokinetic potential). This zeta potential is crucial because it determines the stability of the colloidal system. A high zeta potential (positive or negative) indicates a stable colloid, while a low zeta potential means the particles can come close enough to aggregate and coagulate.

Both Statement I and Statement II are true. The correct answer is Option 3.