The hybridization of boron in the stable borane having thelowest molecular weight is-

Options

A. `sp^(2) `
B. `sp^(3) `
C. `sp `
D. `sp^(3)d`

Answer

To determine the hybridization of boron in the stable borane with the lowest molecular weight, we can follow these steps:

### Step 1: Identify the Borane with the Lowest Molecular Weight
The two common boranes are:
- BH3 (Borane)
- B2H6 (Diborane)

Among these, BH3 has the lowest molecular weight because it consists of one boron atom and three hydrogen atoms.

**Hint:** Look for the simplest borane compound to find the one with the lowest molecular weight.

### Step 2: Determine the Hybridization of Boron in BH3
In BH3, boron is surrounded by three hydrogen atoms. To understand the hybridization, we need to consider the geometry:
- Boron has three valence electrons and forms three single bonds with hydrogen.
- The molecular geometry of BH3 is trigonal planar.

To achieve this geometry, boron undergoes hybridization:
- One 2s orbital and two 2p orbitals mix to form three equivalent sp2 hybrid orbitals.

**Hint:** Recall that the number of regions of electron density around the central atom helps determine the hybridization type.

### Step 3: Confirm the Hybridization
In BH3, the sp2 hybridization leads to:
- 120-degree bond angles between the hydrogen atoms.
- One unhybridized 2p orbital remains, which does not participate in bonding.

This confirms that boron in BH3 is sp2 hybridized.

**Hint:** Visualize the molecular geometry to confirm the hybridization type.

### Conclusion
The hybridization of boron in the stable borane with the lowest molecular weight (BH3) is **sp2**.

**Final Answer:** sp2