A:tetracyanomethane B:carbondioxide
C:Benzene C:1,3-But-di-ene
Ratio of `sigma and pi` bonds is in order:

Options

A. `A=BltCltD`
B. `A=BltDltC`
C. `A=B=C=D`
D. `CltCltAltB`

Answer

To determine the ratio of sigma (σ) and pi (π) bonds in the given compounds, we will analyze each compound step by step.

### Step 1: Tetracyanomethane (C(CN)4)
1. **Structure**: Tetracyanomethane consists of a central carbon atom bonded to four cyano (CN) groups.
2. **Bonds**: Each CN bond consists of 1 sigma bond and 2 pi bonds.
3. **Counting Bonds**:
- **Sigma Bonds**: 4 (one from each CN)
- **Pi Bonds**: 8 (2 from each CN, 2 x 4 = 8)
4. **Ratio**:
\[ \text{Ratio} = \frac{\text{Sigma Bonds}}{\text{Pi Bonds}} = \frac{4}{8} = 0.5 \]

### Step 2: Carbon Dioxide (CO2)
1. **Structure**: Carbon dioxide consists of a central carbon atom double bonded to two oxygen atoms.
2. **Bonds**: Each double bond consists of 1 sigma bond and 1 pi bond.
3. **Counting Bonds**:
- **Sigma Bonds**: 2 (one from each CO bond)
- **Pi Bonds**: 2 (one from each CO bond)
4. **Ratio**:
\[ \text{Ratio} = \frac{2}{2} = 1 \]

### Step 3: Benzene (C6H6)
1. **Structure**: Benzene has a hexagonal ring structure with alternating double bonds.
2. **Bonds**: Each carbon-carbon bond in benzene is a sigma bond, and there are 3 pi bonds due to the double bonds.
3. **Counting Bonds**:
- **Sigma Bonds**: 6 (C-C bonds) + 6 (C-H bonds) = 12
- **Pi Bonds**: 3 (one for each double bond)
4. **Ratio**:
\[ \text{Ratio} = \frac{12}{3} = 4 \]

### Step 4: 1,3-Butadiene (C4H6)
1. **Structure**: 1,3-butadiene has a linear structure with two double bonds between the first and second, and the third and fourth carbons.
2. **Bonds**: Each double bond consists of 1 sigma bond and 1 pi bond.
3. **Counting Bonds**:
- **Sigma Bonds**: 3 (C-C bonds) + 6 (C-H bonds) = 9
- **Pi Bonds**: 2 (one for each double bond)
4. **Ratio**:
\[ \text{Ratio} = \frac{9}{2} = 4.5 \]

### Summary of Ratios
- Tetracyanomethane: 0.5
- Carbon Dioxide: 1
- Benzene: 4
- 1,3-Butadiene: 4.5

### Final Order of Ratios
The order of the ratios of sigma to pi bonds is:
1. Tetracyanomethane: 0.5
2. Carbon Dioxide: 1
3. Benzene: 4
4. 1,3-Butadiene: 4.5

### Conclusion
The ratio of sigma to pi bonds in order is:
**Tetracyanomethane < Carbon Dioxide < Benzene < 1,3-Butadiene**