The molecule which has pyramidal shape is

Options

A. `SO_(3)`
B. `NO_(3)^(-)`
C. `CO_(3)^(2-)`
D. `PF_(3)`

Answer

To determine which molecule has a pyramidal shape, we will analyze the hybridization and geometry of the given options step by step.

### Step 1: Analyze SO3
1. **Valence Electrons Calculation**:
- Sulfur (S) has 6 valence electrons.
- Oxygen (O) has 6 valence electrons and there are 3 oxygen atoms.
- Total = 6 (S) + 3 × 6 (O) = 6 + 18 = 24 valence electrons.

2. **Hybridization**:
- Divide the total valence electrons by 8: 24 / 8 = 3.
- Hybridization = sp² (since it corresponds to 3 electron pairs).

3. **Geometry and Shape**:
- sp² hybridization corresponds to trigonal planar geometry.
- Therefore, SO3 does not have a pyramidal shape.

### Step 2: Analyze HNO3
1. **Valence Electrons Calculation**:
- Nitrogen (N) has 5 valence electrons.
- Oxygen (O) has 6 valence electrons and there are 3 oxygen atoms.
- Total = 5 (N) + 3 × 6 (O) + 1 (negative charge) = 5 + 18 + 1 = 24 valence electrons.

2. **Hybridization**:
- Divide the total valence electrons by 8: 24 / 8 = 3.
- Hybridization = sp².

3. **Geometry and Shape**:
- sp² hybridization corresponds to trigonal planar geometry.
- Therefore, HNO3 does not have a pyramidal shape.

### Step 3: Analyze CO3^2-
1. **Valence Electrons Calculation**:
- Carbon (C) has 4 valence electrons.
- Oxygen (O) has 6 valence electrons and there are 3 oxygen atoms.
- Total = 4 (C) + 3 × 6 (O) + 2 (negative charge) = 4 + 18 + 2 = 24 valence electrons.

2. **Hybridization**:
- Divide the total valence electrons by 8: 24 / 8 = 3.
- Hybridization = sp².

3. **Geometry and Shape**:
- sp² hybridization corresponds to trigonal planar geometry.
- Therefore, CO3^2- does not have a pyramidal shape.

### Step 4: Analyze PF3
1. **Valence Electrons Calculation**:
- Phosphorus (P) has 5 valence electrons.
- Fluorine (F) has 7 valence electrons and there are 3 fluorine atoms.
- Total = 5 (P) + 3 × 7 (F) = 5 + 21 = 26 valence electrons.

2. **Hybridization**:
- Divide the total valence electrons by 8: 26 / 8 = 3.25.
- This indicates 4 electron pairs (3 bond pairs + 1 lone pair).
- Hybridization = sp³.

3. **Geometry and Shape**:
- sp³ hybridization corresponds to tetrahedral geometry.
- However, since there is one lone pair, the shape of PF3 becomes trigonal pyramidal.
- Therefore, PF3 has a pyramidal shape.

### Conclusion
The molecule that has a pyramidal shape is **PF3**.

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