Among the three possible isomers of dibromo benzenes the highest melthing point is possessed by

Options

A. o- dibromobenzene
B. p-dibromobenzene
C. m-dibromobenzene
D. All have same melting point

Answer

To determine which isomer of dibromobenzene has the highest melting point, we need to analyze the three possible isomers: ortho-dibromobenzene, meta-dibromobenzene, and para-dibromobenzene.

### Step 1: Identify the Isomers
The three isomers of dibromobenzene are:
1. Ortho-dibromobenzene (1,2-dibromobenzene)
2. Meta-dibromobenzene (1,3-dibromobenzene)
3. Para-dibromobenzene (1,4-dibromobenzene)

### Step 2: Understand Molecular Symmetry
- **Ortho-dibromobenzene** has two bromine atoms adjacent to each other on the benzene ring.
- **Meta-dibromobenzene** has the bromine atoms separated by one carbon atom.
- **Para-dibromobenzene** has the bromine atoms opposite each other on the benzene ring.

### Step 3: Analyze Melting Points
The melting point of a substance is influenced by its molecular structure and symmetry:
- **Para-dibromobenzene** is symmetrical, allowing for better packing of molecules in the solid state. This close packing leads to stronger intermolecular forces, which results in a higher melting point.
- **Ortho and meta isomers** have less symmetry and do not pack as efficiently, leading to lower melting points compared to para-dibromobenzene.

### Step 4: Conclusion
Among the three isomers, **para-dibromobenzene** possesses the highest melting point due to its symmetrical structure allowing for efficient packing and stronger intermolecular forces.

### Final Answer
**Para-dibromobenzene has the highest melting point among the three isomers of dibromobenzene.**

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