A molecule `XY_2` contains two `sigma`, two `pi` and one lone pair of electron in 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

Explanation

To determine the arrangement of lone pairs and bond pairs in the molecule `XY_2`, we can follow these steps:

### Step 1: Identify the number of bonds and lone pairs
The question states that the molecule `XY_2` contains:
- 2 sigma bonds
- 2 pi bonds
- 1 lone pair of electrons on atom X

### Step 2: Determine the hybridization
In hybridization, we only consider sigma bonds and lone pairs. The total number of regions of electron density around atom X can be calculated as follows:
- 2 sigma bonds contribute 2 regions of electron density.
- 1 lone pair contributes 1 region of electron density.

Thus, the total number of regions of electron density = 2 (from sigma bonds) + 1 (from lone pair) = 3.

The hybridization corresponding to 3 regions of electron density is **sp²**.

### Step 3: Determine the molecular geometry
For an sp² hybridized atom, the arrangement of electron pairs (both bond pairs and lone pairs) is **trigonal planar**. This means that the three regions of electron density (2 sigma bonds and 1 lone pair) will be arranged in a planar configuration around the central atom X.

### Step 4: Determine the shape of the molecule
While the arrangement of electron pairs is trigonal planar, the shape of the molecule will be affected by the presence of the lone pair. The lone pair will occupy one of the positions, leading to a **bent** or **V-shaped** molecular geometry.

### Conclusion
The arrangement of lone pairs and bond pairs in the molecule `XY_2` is trigonal planar, while the molecular shape is bent due to the presence of the lone pair.