The number of double bonds in gammexane is

Options

A. 0
B. 1
C. 2
D. 3

Explanation

To determine the number of double bonds in gammexane (also known as benzene hexachloride or BHC), we can follow these steps:

### Step 1: Understand the Structure of Gammexane
Gammexane is derived from benzene through the chlorination process. The structure of gammexane consists of a benzene ring with six chlorine atoms attached to it.

### Step 2: Analyze the Benzene Ring
Benzene (C6H6) is a cyclic compound that contains alternating single and double bonds. However, due to resonance, benzene is often represented as having a delocalized pi-electron system rather than distinct double bonds.

### Step 3: Consider the Chlorination Reaction
When benzene undergoes chlorination, it replaces hydrogen atoms with chlorine atoms. In the case of gammexane, all six hydrogen atoms in benzene are replaced by chlorine atoms, resulting in C6Cl6.

### Step 4: Determine the Degree of Unsaturation
The degree of unsaturation can be calculated using the formula:
\[ \text{Degree of Unsaturation} = \frac{(2C + 2 + N - H - X)}{2} \]
where:
- C = number of carbon atoms
- H = number of hydrogen atoms
- N = number of nitrogen atoms (not applicable here)
- X = number of halogen atoms (in this case, chlorine)

For gammexane (C6Cl6):
- C = 6
- H = 0 (since all H are replaced by Cl)
- X = 6 (the six chlorine atoms)

Plugging in the values:
\[ \text{Degree of Unsaturation} = \frac{(2 \times 6 + 2 + 0 - 0 - 6)}{2} = \frac{(12 + 2 - 6)}{2} = \frac{8}{2} = 4 \]

### Step 5: Identify the Number of Double Bonds
While the degree of unsaturation indicates the presence of rings or double bonds, in the case of gammexane, the chlorination has saturated the compound. Therefore, despite the degree of unsaturation being 4, there are no actual double bonds present in the structure of gammexane.

### Conclusion
Thus, the number of double bonds in gammexane is **0**.