The ratio of `sigma` bond and `pi` bond in naphthalene is

Options

A. 11:5
B. 2:1
C. 19:5
D. 10:4

Answer

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

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

**Hint:** Remember that each carbon in benzene forms three sigma bonds and one pi bond.

### Step 2: Draw the Structure of Naphthalene
Draw the structure of naphthalene, which consists of 10 carbon atoms and 8 hydrogen atoms. The structure shows that the two benzene rings share two carbon atoms.

**Hint:** Visualizing the structure can help in counting the bonds accurately.

### Step 3: Count the Sigma Bonds
In naphthalene:
- Each carbon-carbon (C-C) single bond is a sigma bond.
- Each carbon-hydrogen (C-H) bond is also a sigma bond.

For naphthalene:
- There are 10 C-C bonds (including the shared ones).
- There are 8 C-H bonds.

Total sigma bonds = C-C bonds + C-H bonds = 10 + 8 = 18 sigma bonds.

**Hint:** Count all the single bonds carefully, including those between carbons and hydrogens.

### Step 4: Count the Pi Bonds
In naphthalene:
- Each double bond contributes one pi bond.

Naphthalene has 5 double bonds (from the alternating double bonds in the two benzene rings).

Total pi bonds = 5.

**Hint:** Remember that each double bond consists of one sigma bond and one pi bond.

### Step 5: Calculate the Ratio of Sigma to Pi Bonds
Now, we can find the ratio of sigma bonds to pi bonds.

Ratio = Number of Sigma Bonds : Number of Pi Bonds = 18 : 5.

**Hint:** Simplifying the ratio can help in understanding the relationship between the two types of bonds.

### Final Answer
The ratio of sigma bonds to pi bonds in naphthalene is 18:5.

### Summary of Steps:
1. Understand the structure of naphthalene.
2. Draw the structure.
3. Count the sigma bonds (C-C and C-H).
4. Count the pi bonds (from double bonds).
5. Calculate the ratio of sigma to pi bonds.