Total number of `sigma` and `pi `-bonds are in naphthalene is

Options

A. `5 pi " and " 18 sigma`
B. `6pi " and " 19 sigma`
C. `5 pi " and " 19 sigma`
D. `7 pi " and " 26 sigma`

Answer

To determine the total number of sigma (σ) and pi (π) bonds in naphthalene, we can follow these steps:

### Step 1: Draw the Structure of Naphthalene
Naphthalene consists of two fused benzene rings. Each benzene ring has a hexagonal structure with alternating double bonds.

### Step 2: Count the Carbon-Carbon Bonds
In naphthalene, there are 10 carbon atoms. The structure has 5 double bonds between the carbon atoms. Each double bond consists of one sigma bond and one pi bond.

- **Total Carbon-Carbon Bonds**:
- There are 5 double bonds contributing 5 σ bonds and 5 π bonds.
- Additionally, there are 5 single bonds between the remaining carbon atoms.

### Step 3: Calculate the Total Number of Sigma Bonds
- From the 5 double bonds, we have 5 σ bonds.
- The remaining carbon atoms contribute 5 additional σ bonds from the single bonds.
- Each carbon atom is also bonded to hydrogen atoms. In naphthalene, there are 8 hydrogen atoms, and each C-H bond is a σ bond.

**Total σ Bonds Calculation**:
- σ bonds from C-C: 5 (from double bonds) + 5 (from single bonds) = 10 σ bonds
- σ bonds from C-H: 8 σ bonds

**Total σ Bonds** = 10 + 8 = 18 σ bonds.

### Step 4: Count the Pi Bonds
As mentioned earlier, each of the 5 double bonds contributes one π bond.

**Total π Bonds** = 5 π bonds.

### Final Count
- Total σ Bonds = 18
- Total π Bonds = 5

### Conclusion
The total number of sigma and pi bonds in naphthalene is:
- **Total σ Bonds** = 18
- **Total π Bonds** = 5

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