Covalence for central atom is maximum in

Options

A. `BF_3`
B. `SO_2Cl_2`
C. `POCl_3`
D. `BeCl_2`

Answer

To determine which compound has the maximum covalence for the central atom, we need to analyze each option provided in the question. Covalence refers to the number of bonds that the central atom can form with surrounding atoms. Let's evaluate each compound step by step:

### Step 1: Analyze BF3 (Boron Trifluoride)
- **Central Atom**: Boron (B)
- **Structure**: BF3 has a trigonal planar geometry.
- **Bonds Formed**: Boron forms 3 single bonds with 3 fluorine atoms.
- **Covalence**: The covalence of boron in BF3 is **3**.

### Step 2: Analyze SO2Cl2 (Sulfur Oxychloride)
- **Central Atom**: Sulfur (S)
- **Structure**: SO2Cl2 has a structure where sulfur is double-bonded to two oxygen atoms and single-bonded to two chlorine atoms.
- **Bonds Formed**: Sulfur forms 2 double bonds (2 pi and 2 sigma) with oxygen and 2 single bonds (sigma) with chlorine.
- **Covalence**: The total number of bonds around sulfur is **6** (2 from O and 2 from Cl). Thus, the covalence of sulfur in SO2Cl2 is **6**.

### Step 3: Analyze POCl3 (Phosphorus Oxychloride)
- **Central Atom**: Phosphorus (P)
- **Structure**: POCl3 has phosphorus double-bonded to one oxygen atom and single-bonded to three chlorine atoms.
- **Bonds Formed**: Phosphorus forms 1 double bond (1 pi and 1 sigma) with oxygen and 3 single bonds (sigma) with chlorine.
- **Covalence**: The total number of bonds around phosphorus is **5** (1 from O and 3 from Cl). Thus, the covalence of phosphorus in POCl3 is **5**.

### Step 4: Analyze BeCl2 (Beryllium Chloride)
- **Central Atom**: Beryllium (Be)
- **Structure**: BeCl2 has a linear structure.
- **Bonds Formed**: Beryllium forms 2 single bonds with 2 chlorine atoms.
- **Covalence**: The covalence of beryllium in BeCl2 is **2**.

### Conclusion
Now, we can summarize the covalence for each central atom:
- **BF3**: Covalence = 3
- **SO2Cl2**: Covalence = 6
- **POCl3**: Covalence = 5
- **BeCl2**: Covalence = 2

The compound with the maximum covalence for the central atom is **SO2Cl2**, with a covalence of **6**.

### Final Answer
**SO2Cl2 has the maximum covalence of 6 for the central atom.**

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