The shape of `NH_(3)` is very similar to that of :

Options

A. `BH_(3)`
B. `CH_(3)^(-)`
C. `CH_(3)^(+)`
D. `SO_(4)^(2-)`

Explanation

To determine the shape of NH₃ (ammonia) and find a similar structure from the given options, we can follow these steps:

### Step 1: Identify the central atom and its valency
- The central atom in NH₃ is nitrogen (N).
- The valency of nitrogen is 3, as it forms three sigma bonds with hydrogen atoms.

### Step 2: Determine the number of lone pairs
- In NH₃, nitrogen has one lone pair of electrons after forming three bonds with hydrogen atoms.

### Step 3: Analyze the molecular geometry
- The presence of one lone pair and three bond pairs leads to a pyramidal shape due to the repulsion between the lone pair and the bond pairs. This is known as trigonal pyramidal geometry.

### Step 4: Compare with given options
1. **Option A: BCl₃**
- Central atom: Boron (B)
- Valency: 3 (forms three bonds)
- Geometry: Trigonal planar (no lone pairs)
- **Conclusion**: Not similar to NH₃.

2. **Option B: CH₃⁻**
- Central atom: Carbon (C)
- Valency: 4 (three bonds + one extra electron due to negative charge)
- Geometry: Pyramidal (similar to NH₃ due to lone pair effect)
- **Conclusion**: Similar to NH₃.

3. **Option C: CH₃⁺**
- Central atom: Carbon (C)
- Valency: 4 (three bonds, no lone pairs due to positive charge)
- Geometry: Trigonal planar
- **Conclusion**: Not similar to NH₃.

4. **Option D: SO₄²⁻**
- Central atom: Sulfur (S)
- Valency: 6 (forms four bonds with oxygen)
- Geometry: Tetrahedral (no lone pairs)
- **Conclusion**: Not similar to NH₃.

### Step 5: Final Conclusion
- The only option that has a shape similar to NH₃ (pyramidal) is **Option B: CH₃⁻**.

### Final Answer
The shape of NH₃ is very similar to that of **CH₃⁻**.

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