Which one of the following molecules contains no `pi` - bond ?

Options

A. `CO_2`
B. `H_2O`
C. `SO_2`
D. `NO_2`

Explanation

To determine which molecule contains no pi bonds, we will analyze the molecular structures of the given options. Let's break it down step by step:

### Step 1: Analyze CO2 (Carbon Dioxide)
- **Structure**: Carbon (C) has 4 valence electrons and forms two double bonds with two oxygen (O) atoms.
- **Bonds**: Each double bond consists of one sigma (σ) bond and one pi (π) bond.
- **Conclusion**: CO2 has 2 pi bonds.

### Step 2: Analyze H2O (Water)
- **Structure**: Oxygen (O) has 6 valence electrons and forms two single bonds with two hydrogen (H) atoms.
- **Bonds**: Each single bond is a sigma (σ) bond.
- **Conclusion**: H2O has no pi bonds.

### Step 3: Analyze SO2 (Sulfur Dioxide)
- **Structure**: Sulfur (S) has 6 valence electrons and forms two double bonds with two oxygen (O) atoms.
- **Bonds**: Each double bond consists of one sigma (σ) bond and one pi (π) bond.
- **Conclusion**: SO2 has 2 pi bonds.

### Step 4: Analyze NO2 (Nitrogen Dioxide)
- **Structure**: Nitrogen (N) has 5 valence electrons and forms two bonds with two oxygen (O) atoms, one of which is a double bond.
- **Bonds**: The double bond consists of one sigma (σ) bond and one pi (π) bond, while the other bond is a sigma bond.
- **Conclusion**: NO2 has 2 pi bonds.

### Final Conclusion
Among the given molecules, H2O is the only one that contains no pi bonds.

### Summary
- CO2: 2 pi bonds
- H2O: 0 pi bonds (Answer)
- SO2: 2 pi bonds
- NO2: 2 pi bonds

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