Intermolecular forces between n-hexane and n-heptane are nearly same as between hexane and heptane individually. When these two are mixed, which of the following is not true about the solution formed ?

Options

A. It obeys Raoult's law, i.e. `p_(A)=x_(A)p_(A)^(@) and p_(B)=x_(B)p_(B)^(@)`
B. `DeltaH_("mixing")` is zero
C. `DeltaV_("mixing")` is zero
D. Its forms minimum boiling azeotrope

Answer

To solve the question regarding the mixing of n-hexane and n-heptane, we need to analyze the properties of the solution formed and identify which statement about the solution is not true.

### Step-by-Step Solution:

1. **Understanding Intermolecular Forces**:
- n-Hexane (C6H14) and n-Heptane (C7H16) are both alkanes and have similar types of intermolecular forces, primarily London dispersion forces.
- The question states that the intermolecular forces between n-hexane and n-heptane are nearly the same as those between hexane and heptane individually.

**Hint**: Consider the types of intermolecular forces present in similar molecules.

2. **Ideal Solution Concept**:
- When two substances are mixed and their intermolecular forces are similar, they can be considered to form an ideal solution.
- According to Raoult's Law, in an ideal solution, the partial vapor pressures of the components are directly proportional to their mole fractions.

**Hint**: Recall the definition of an ideal solution and Raoult's Law.

3. **Enthalpy of Mixing (ΔH)**:
- For an ideal solution, the enthalpy change upon mixing (ΔH) is zero. This is because the interactions between different molecules (AB interactions) are similar to the interactions within each component (AA and BB interactions).

**Hint**: Remember that ΔH = 0 indicates no heat is absorbed or released during mixing.

4. **Volume Change upon Mixing (ΔV)**:
- Similarly, the volume change upon mixing (ΔV) is also zero for an ideal solution. This means that the total volume after mixing is equal to the sum of the individual volumes of the components.

**Hint**: Think about how volume behaves when similar substances are mixed.

5. **Azeotropes Formation**:
- Azeotropes are mixtures that exhibit non-ideal behavior, often resulting in a constant boiling point and composition. They are typically formed by solutions where the interactions between different molecules are significantly different from those within the pure components.
- Since n-hexane and n-heptane form an ideal solution, they do not form minimum boiling azeotropes.

**Hint**: Recall the characteristics of azeotropes and their relation to ideal vs. non-ideal solutions.

### Conclusion:
Based on the analysis, the statement that is **not true** about the solution formed by mixing n-hexane and n-heptane is that it formed minimum boiling azeotropes. This is incorrect because the solution behaves ideally.

### Final Answer:
The incorrect statement is: "It formed minimum boiling azeotropes."