In which compound compounds vacant hybride orbitals take part in bonding:

Options

A. `B_(2)H_(6)`
B. `Al_(2)Cl_(6)`
C. `C_(2)H_(5)Cl`
D. `H_(3)BO_(3)`

Answer

To determine in which compounds vacant hybrid orbitals take part in bonding, we will analyze the hybridization and bonding characteristics of the given compounds. Let's go through the analysis step-by-step.

### Step 1: Analyze the first compound, B2H6 (Diborane)
1. **Identify the central atom and its electronic configuration**: Boron (B) has an electronic configuration of \(1s^2 2s^2 2p^1\).
2. **Hybridization**: In diborane, each boron atom undergoes sp³ hybridization. However, one of the hybrid orbitals remains vacant.
3. **Bonding**: The vacant hybrid orbital can participate in bonding with hydrogen atoms, forming three-center two-electron bonds. Thus, vacant hybrid orbitals do take part in bonding in B2H6.

### Step 2: Analyze the second compound, C2H5Cl (Ethyl Chloride)
1. **Identify the central atom and its electronic configuration**: The carbon atom has an electronic configuration of \(1s^2 2s^2 2p^2\).
2. **Hybridization**: Each carbon atom in ethyl chloride undergoes sp³ hybridization, forming four sigma bonds (three with hydrogen and one with chlorine).
3. **Bonding**: All hybrid orbitals are involved in bonding, and there are no vacant hybrid orbitals. Therefore, vacant hybrid orbitals do not take part in bonding in C2H5Cl.

### Step 3: Analyze the third compound, Al2Cl6 (Aluminum Chloride Dimer)
1. **Identify the central atom and its electronic configuration**: Aluminum (Al) has an electronic configuration of \(3s^2 3p^1\).
2. **Hybridization**: In AlCl3, aluminum undergoes sp² hybridization, which leaves one vacant hybrid orbital.
3. **Bonding**: In the dimer Al2Cl6, the vacant hybrid orbitals of aluminum can accept lone pairs from chlorine atoms, thus participating in bonding. Therefore, vacant hybrid orbitals do take part in bonding in Al2Cl6.

### Summary of Findings
- **B2H6**: Vacant hybrid orbitals participate in bonding.
- **C2H5Cl**: No vacant hybrid orbitals participate in bonding.
- **Al2Cl6**: Vacant hybrid orbitals participate in bonding.

### Conclusion
The compounds in which vacant hybrid orbitals take part in bonding are **B2H6** and **Al2Cl6**.

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