In the following question, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices:
Assertion: Colloidal solutions shows colligative properties .
Reason : Colloidal particles are large in size .
Answer & explanation
Correct answer: option 2
Assertion: Colloidal solutions show colligative properties. This assertion is correct. Colligative properties are properties that depend on the number of solute particles in a solution, regardless of their nature. These properties include boiling point elevation, freezing point depression, vapor pressure lowering, and osmotic pressure. Colligative properties are primarily related to the concentration of particles and do not depend on the size or nature of the particles.
Reason: Colloidal particles are large in size. This reason is also correct. Colloidal particles are larger than individual ions or small molecules. They typically have a size range between 1 and 1000 nanometers. The larger size of colloidal particles is what distinguishes them from true solutions where the solute particles are much smaller and do not scatter light.
However, the reason provided does not explain why colloidal solutions show colligative properties. Colligative properties are related to the concentration of solute particles, whereas the reason focuses on the size of colloidal particles. The assertion and reason are correct independently, but the reason does not provide an explanation for the colligative properties exhibited by colloidal solutions.
Therefore, Assertion and reason both are correct, but the reason does not explain the assertion.
Or
Colloidal particles being bigger aggregates, the number of particles in a colloidal solution is comparatively small as compared to a true solution. Hence, the values of colligative properties (osmotic pressure, lowering in vapour pressure, depression in freezing point and elevation in boiling point) are of small order as compared to values shown by true solutions at same concentration.