Question

Statement I: For colloidal particles, the values of colligative properties are of small order as compared to values shown by true solutions at the same concentration 
Statement II: For colloidal particles, the potential difference between the fixed layer and the diffused layer of the 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

• A. Statement I is false but Statement II is true
• B. Both Statement I and Statement II are true
• C. Statement I is true but Statement II is false
• D. Both Statement I and Statement II are false

Answer 1

The Correct Option is B

To determine the correctness of the given statements, we need to analyze each statement based on our understanding of colloidal particles and their properties:

1. Statement I: For colloidal particles, the values of colligative properties are of small order as compared to values shown by true solutions at the same concentration.
   • Colligative properties (such as boiling point elevation, freezing point depression, osmotic pressure, and vapor pressure lowering) depend on the number of solute particles in a solution.
   • In a true solution, the solute particles (molecules or ions) are much smaller and more numerous than in a colloidal solution at the same concentration.
   • Colloidal particles are larger aggregates, which means fewer particles per unit volume, leading to significantly lower colligative properties compared to true molecular solutions at equal concentration.
2. Statement II: For colloidal particles, the potential difference between the fixed layer and the diffused layer of the same charges is called the electrokinetic potential or zeta potential.
   • Zeta potential is indeed defined as the electrokinetic potential at the slipping plane of a colloidal particle.
   • This potential difference is between the compact or fixed layer (directly attached to the particle surface) and the surrounding diffuse layer in the dispersion medium.
   • Zeta potential is a measure of the stability of colloids; higher zeta potentials indicate greater stability and resistance to aggregation.

Considering the explanations above, both statements correctly describe the properties of colloidal particles. Therefore, the correct answer is:

Both Statement I and Statement II are true