Which of the following characteristics is not possessed by n ideal solution ?

Options

A. Obeys Raoult's law
B. Volume change on mixing is not equal to zero
C. There should be no chemical reaction between solute and solvent.
D. Only very dilute solutions behave as ideal solutions.

Answer

To determine which characteristic is not possessed by an ideal solution, we need to understand the properties of ideal solutions. Here’s a step-by-step solution:

### Step 1: Understand the Definition of an Ideal Solution
An ideal solution is one in which the interactions between the different components (solute and solvent) are similar to the interactions between the molecules of the same component. This means that the solution behaves ideally under certain conditions.

**Hint:** Recall that ideal solutions follow Raoult's law, where the vapor pressure of each component is proportional to its mole fraction.

### Step 2: Identify the Characteristics of Ideal Solutions
1. **Raoult's Law**: The partial pressure of each component in an ideal solution is equal to the vapor pressure of the pure component multiplied by its mole fraction in the solution.
2. **Enthalpy of Mixing (ΔH mixing)**: For an ideal solution, the enthalpy change upon mixing is zero (ΔH mixing = 0). This means there is no heat absorbed or released when the solute is dissolved in the solvent.
3. **Volume Change on Mixing (ΔV mixing)**: The volume change upon mixing is also zero (ΔV mixing = 0).
4. **Entropy of Mixing**: The entropy of mixing is positive and does not equal zero.

**Hint:** Focus on the conditions under which the properties of mixing (enthalpy, volume, and entropy) are considered for ideal solutions.

### Step 3: Analyze the Given Options
Now, let's consider the options provided in the question (not explicitly listed, but we can infer based on common characteristics):
- A characteristic that states "ΔH mixing = 0" is true for ideal solutions.
- A characteristic that states "ΔV mixing = 0" is also true for ideal solutions.
- A characteristic that states "ΔS mixing > 0" is true for ideal solutions.
- A characteristic that states "Chemical reactions occur" is not true for ideal solutions.

**Hint:** Look for a characteristic that contradicts the properties of ideal solutions, particularly those that involve changes in energy or volume.

### Step 4: Conclusion
The characteristic that is not possessed by an ideal solution is the occurrence of chemical reactions during the mixing process. Ideal solutions do not undergo chemical reactions; they simply mix without any change in the chemical nature of the components.

**Final Answer:** The characteristic that is not possessed by an ideal solution is the occurrence of chemical reactions.