A molecule `XY_(2)` contains two `sigma` bonds two `pi` bond and one lone pair of electrons in the valence shell of `X`. The arrangement of lone pair as well as bond pairs is

Options

A. square pyramidal
B. linear
C. Trigonal planar
D. unpredictable

Answer

To determine the arrangement of lone pairs and bond pairs in the molecule \( XY_2 \) with the given characteristics, we can follow these steps:

### Step 1: Analyze the given information
The molecule \( XY_2 \) has:
- 2 sigma bonds
- 2 pi bonds
- 1 lone pair of electrons on the central atom \( X \)

### Step 2: Determine the hybridization of the central atom \( X \)
Given that there are 2 sigma bonds and 2 pi bonds, we can deduce the hybridization:
- Each sigma bond corresponds to one hybrid orbital.
- Each pi bond corresponds to unhybridized p orbitals.

Since there are 2 sigma bonds and 2 pi bonds, the central atom \( X \) must be involved in sp hybridization:
- In sp hybridization, there are 2 hybrid orbitals (for the 2 sigma bonds) and 2 unhybridized p orbitals (for the 2 pi bonds).

### Step 3: Consider the lone pair
With 1 lone pair of electrons on \( X \), we need to account for this in the geometry:
- The presence of a lone pair will affect the molecular geometry.

### Step 4: Determine the molecular geometry
In sp hybridization with 2 sigma bonds and 1 lone pair, the arrangement of the electron pairs (both bonding and lone pairs) will adopt a linear geometry. This is because:
- The 2 sigma bonds will be 180 degrees apart, and the lone pair will occupy one of the positions in a way that minimizes repulsion.

### Step 5: Final arrangement
Thus, the arrangement of the lone pair and bond pairs in \( XY_2 \) is linear.

### Conclusion
The arrangement of lone pairs and bond pairs in the molecule \( XY_2 \) is linear.

---