Which of the following has pyramidal structure ?

Options

A. `NH_(3)`
B. `BF_(3)`
C. `C Cl_(4)`
D. `H_(2)O.`

Answer

To determine which of the following compounds has a pyramidal structure, we will analyze the molecular geometry of each compound mentioned: ammonia (NH3), boron trifluoride (BF3), carbon tetrachloride (CCl4), and water (H2O).

### Step 1: Analyze Ammonia (NH3)
1. **Valence Electrons**: Nitrogen has 5 valence electrons.
2. **Bond Formation**: It forms 3 bonds with hydrogen atoms, using 3 of its valence electrons.
3. **Lone Pair**: This leaves 1 lone pair on the nitrogen atom.
4. **Geometry**: The presence of 1 lone pair and 3 bond pairs leads to a pyramidal shape (specifically, trigonal pyramidal).

### Step 2: Analyze Boron Trifluoride (BF3)
1. **Valence Electrons**: Boron has 3 valence electrons.
2. **Bond Formation**: It forms 3 bonds with fluorine atoms, using all its valence electrons.
3. **Lone Pair**: There are no lone pairs on boron.
4. **Geometry**: The structure is trigonal planar due to the absence of lone pairs.

### Step 3: Analyze Carbon Tetrachloride (CCl4)
1. **Valence Electrons**: Carbon has 4 valence electrons.
2. **Bond Formation**: It forms 4 bonds with chlorine atoms, using all its valence electrons.
3. **Lone Pair**: There are no lone pairs on carbon.
4. **Geometry**: The structure is tetrahedral due to the absence of lone pairs.

### Step 4: Analyze Water (H2O)
1. **Valence Electrons**: Oxygen has 6 valence electrons.
2. **Bond Formation**: It forms 2 bonds with hydrogen atoms, using 2 of its valence electrons.
3. **Lone Pairs**: This leaves 2 lone pairs on the oxygen atom.
4. **Geometry**: The presence of 2 lone pairs and 2 bond pairs leads to a bent or V-shaped structure.

### Conclusion
After analyzing all the compounds, we find that the only compound with a pyramidal structure is **Ammonia (NH3)**.

### Final Answer
**Ammonia (NH3) has a pyramidal structure.**

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