surface tension of lyophilic sols is

Options

A. lower than water
B. more than water
C. equal to water
D. none of these

Answer

To determine the surface tension of lyophilic sols, we can analyze the properties of these sols in relation to water. Here's a step-by-step solution:

### Step 1: Understand the Definition of Surface Tension
Surface tension is the property of a liquid's surface that allows it to resist an external force, due to the cohesive nature of its molecules. It is typically measured in dynes per centimeter (dyne/cm).

**Hint:** Remember that surface tension is influenced by the interactions between molecules in the liquid.

### Step 2: Define Lyophilic Sols
Lyophilic sols are colloidal systems where the dispersed phase (particles) has a strong affinity for the dispersion medium (solvent). In this case, we are considering lyophilic sols in water.

**Hint:** Think about how the affinity between the dispersed phase and the solvent affects the overall properties of the sol.

### Step 3: Compare with Water
Water has a relatively high surface tension due to strong hydrogen bonding between its molecules. When lyophilic colloids are added to water, they interact favorably with water molecules.

**Hint:** Consider how the interactions between the lyophilic particles and water molecules might change the arrangement and behavior of water molecules at the surface.

### Step 4: Effect on Surface Tension
The presence of lyophilic colloids disrupts the cohesive forces among water molecules at the surface. This disruption leads to a decrease in surface tension compared to pure water.

**Hint:** Think about how adding substances that interact well with water can alter the balance of forces at the surface.

### Step 5: Conclusion
Since the surface tension of lyophilic sols is lower than that of pure water due to the strong affinity of the colloids for the solvent, the correct answer to the question is that the surface tension of lyophilic sols is lower than that of water.

**Final Answer:** The surface tension of lyophilic sols is lower than that of water.

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