`sigma_(sp^2 - s)` bond is present in

Options

A. `CH_4`
B. `NH_3`
C. `SiCl_4`
D. `CH_2 = CH Cl`

Answer

To determine where a sigma sp²-s bond is present, we need to analyze the hybridization of the central atom in each given compound. Let's go through the options step by step.

### Step 1: Analyze CH₄ (Methane)
- **Structure**: CH₄ has one carbon atom bonded to four hydrogen atoms.
- **Hybridization**: The carbon atom in CH₄ is sp³ hybridized because it forms four sigma bonds with hydrogen atoms.
- **Bonding**: The bond formed between the sp³ hybrid orbital of carbon and the s orbital of hydrogen is an sp³-s bond.
- **Conclusion**: CH₄ does not have an sp²-s bond.

### Step 2: Analyze NH₃ (Ammonia)
- **Structure**: NH₃ has one nitrogen atom bonded to three hydrogen atoms and one lone pair.
- **Hybridization**: The nitrogen atom in NH₃ is also sp³ hybridized as it forms three sigma bonds and has one lone pair.
- **Bonding**: The bond formed between the sp³ hybrid orbital of nitrogen and the s orbital of hydrogen is an sp³-s bond.
- **Conclusion**: NH₃ does not have an sp²-s bond.

### Step 3: Analyze SiCl₄ (Silicon Tetrachloride)
- **Structure**: SiCl₄ has one silicon atom bonded to four chlorine atoms.
- **Hybridization**: The silicon atom in SiCl₄ is sp³ hybridized because it forms four sigma bonds with chlorine atoms.
- **Bonding**: The bond formed between the sp³ hybrid orbital of silicon and the p orbital of chlorine is an sp³-p bond.
- **Conclusion**: SiCl₄ does not have an sp²-s bond.

### Step 4: Analyze CH₂=CHCl (Vinyl Chloride)
- **Structure**: CH₂=CHCl has a double bond between two carbon atoms and one chlorine atom bonded to one of the carbons.
- **Hybridization**: The carbon atoms in CH₂=CHCl are sp² hybridized. The first carbon forms two sigma bonds (one with hydrogen and one with the second carbon) and one pi bond (with the second carbon), while the second carbon forms two sigma bonds (one with hydrogen and one with chlorine) and one pi bond (with the first carbon).
- **Bonding**: The bond formed between the sp² hybrid orbital of carbon and the s orbital of hydrogen is an sp²-s bond, and the bond formed between the sp² hybrid orbital of carbon and the s orbital of chlorine is also an sp²-s bond.
- **Conclusion**: CH₂=CHCl has an sp²-s bond.

### Final Answer
The compound that contains a sigma sp²-s bond is **CH₂=CHCl** (option D).

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