Does the vapour vapour of the solution is effected in both the cases equally and why ????Case 1 if non volatile solute is present on the surface Case 2 if non volatile solute is present on the bottom

To address your question about how the vapor of a solution is affected by the presence of a non-volatile solute, we need to consider the principles of vapor pressure and how solutes interact with solvents. The two cases you mentioned—where the non-volatile solute is either on the surface or at the bottom—can lead to different scenarios, but the overall effect on vapor pressure remains consistent due to the nature of non-volatile solutes.

Understanding Vapor Pressure

Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid or solid phase. When a non-volatile solute is added to a solvent, it lowers the vapor pressure of the solvent. This occurs because the solute molecules occupy space at the surface of the liquid, reducing the number of solvent molecules that can escape into the vapor phase.

Case 1: Non-Volatile Solute at the Surface

In this scenario, the non-volatile solute is directly interacting with the surface of the solution. Here’s what happens:

• The solute molecules block some of the solvent molecules from escaping into the vapor phase.
• This leads to a reduction in the number of solvent molecules available to exert vapor pressure.
• As a result, the vapor pressure of the solution is lower than that of the pure solvent.

Case 2: Non-Volatile Solute at the Bottom

When the non-volatile solute is at the bottom of the container, the situation is slightly different, but the effect on vapor pressure is still significant:

• The solute at the bottom does not directly block solvent molecules at the surface, but it still contributes to the overall concentration of solute in the solution.
• As the solvent molecules at the surface evaporate, they still encounter the solute molecules in the bulk of the solution, which affects the equilibrium.
• Thus, the presence of the solute still lowers the vapor pressure of the solution compared to the pure solvent.

Comparative Analysis

In both cases, the presence of the non-volatile solute results in a decrease in vapor pressure. The key difference lies in how the solute is positioned:

• When at the surface, the solute directly obstructs solvent molecules from escaping.
• When at the bottom, the solute influences the vapor pressure indirectly through its concentration in the solution.

Conclusion on Vapor Pressure Effects

Ultimately, while the mechanisms may differ slightly based on the position of the non-volatile solute, the effect on vapor pressure is fundamentally the same: it decreases due to the presence of the solute. This principle is crucial in understanding colligative properties, which are properties that depend on the number of solute particles in a solution rather than their identity.

In summary, regardless of whether the non-volatile solute is at the surface or the bottom, it will lower the vapor pressure of the solution compared to that of the pure solvent, demonstrating the consistent impact of solutes on vapor behavior in solutions.