Question

Assertion: Lyophilic colloids have a unique property of protecting lyophobic colloids.
Reason: Lyophilic colloids are extensively solvated.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect

Answer 1

Before we move on to answer this we should be knowing the meaning of lyophilic colloids. Find out the affinity of particles of the dispersion phase and dispersion medium in lyophilic colloids. Defining the lyophilic colloids will give us an idea about the properties of the lyophilic colloids. And then we can justify the assertion, mentioned in the question.

Complete step by step solution:
We should know that lyophilic colloids have a unique property of protecting lyophobic colloids. When a lyophilic solution is added to the lyophobic solution, the lyophilic particles form a layer around lyophobic particles and thus isolate the latter from electrolytes. These colloids are known as lyophilic protective colloids.
Lyophilic colloids are the colloids in which the particles of the dispersed phase (solute) have a strong affinity towards particles of the dispersion medium (solvent).
Lyophilic solutions are more stable than lyophobic solutions due to the fact that lyophilic colloids are solvated to a great extent. This means that the colloidal particles are covered by a sheath of the liquid in which they are dispersed.
Hence, we can say that both assertion and reason are the correct but the reason is not the correct explanation for the assertion.

So, the correct answer is Option B.

Note: We should know that lyophilic colloids are reversible as well as irreversible. This is because on evaporating the liquid, the residue left will pass into a colloidal state on the addition of the liquid. This makes the lyophilic colloids reversible. But, the fact that on evaporating the liquid, the residue left cannot be converted into solution on mere addition of liquid, makes the Lyophilic colloids as irreversible.