Which one of the following is non-ideal solution?

Options

A. Benzene + toluene
B. n-hexane + n-heptane
C. Ethyl bromide + ethyl iodide
D. `C""Cl_4 +CHCl_3`

Answer

To determine which of the given solutions is a non-ideal solution, we will analyze the options based on the principles of Raoult's law and the molecular structures of the components involved.

### Step-by-Step Solution:

1. **Understand Raoult's Law**:
- Raoult's law states that the vapor pressure of an ideal solution is directly proportional to the mole fraction of the solvent. Ideal solutions are those that obey Raoult's law, while non-ideal solutions do not.

2. **Identify Ideal vs. Non-Ideal Solutions**:
- Ideal solutions are formed when the components have similar molecular structures (e.g., similar functional groups, similar sizes).
- Non-ideal solutions arise when the components have dissimilar molecular structures.

3. **Examine the Given Options**:
- **Option 1: Benzene and Toluene**: Both have similar structures (aromatic rings), thus they form an ideal solution.
- **Option 2: n-Hexane and n-Heptane**: Both are alkanes with similar structures, hence they also form an ideal solution.
- **Option 3: Ethyl Bromide and Ethyl Iodide**: Both belong to the same family of compounds and have similar structures, indicating they are ideal.
- **Option 4: CCl4 (Carbon Tetrachloride) and CHCl3 (Chloroform)**: These two compounds have different molecular structures. CCl4 is a tetrahedral molecule, while CHCl3 has a different geometry due to the presence of hydrogen, indicating dissimilarity.

4. **Conclusion**:
- Based on the analysis, the only pair that does not have a similar molecular structure is CCl4 and CHCl3. Therefore, this pair represents a non-ideal solution.

### Final Answer:
The non-ideal solution is **Option 4: CCl4 and CHCl3**.

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