Out of `SO_2, BeCl_2, O_3, H_2O and HgCl_2`, the linear species are

Options

A. `SO_2 and O_3`
B. `SO_2 and H_2O`
C. `BeCl_2 and HgCl_2`
D. `O_3 and H_2O`

Explanation

To determine which of the given species are linear, we will analyze the molecular geometry of each compound: SO₂, BeCl₂, O₃, H₂O, and HgCl₂.

### Step 1: Analyze SO₂ (Sulfur Dioxide)
- SO₂ has a bent molecular geometry due to the presence of one lone pair on the sulfur atom and two double bonds with oxygen. The bond angle is approximately 120 degrees.
- **Conclusion**: SO₂ is **not linear**.

### Step 2: Analyze BeCl₂ (Beryllium Chloride)
- BeCl₂ has a linear molecular geometry. Beryllium has no lone pairs and forms two single bonds with chlorine atoms, resulting in a bond angle of 180 degrees.
- **Conclusion**: BeCl₂ is **linear**.

### Step 3: Analyze O₃ (Ozone)
- O₃ has a bent molecular geometry due to the presence of a lone pair on the central oxygen atom. The bond angle is approximately 117 degrees.
- **Conclusion**: O₃ is **not linear**.

### Step 4: Analyze H₂O (Water)
- H₂O has a bent molecular geometry due to the two lone pairs on the oxygen atom. The bond angle is about 104.5 degrees.
- **Conclusion**: H₂O is **not linear**.

### Step 5: Analyze HgCl₂ (Mercury(II) Chloride)
- HgCl₂ has a linear molecular geometry. Mercury forms two single bonds with chlorine atoms, resulting in a bond angle of 180 degrees.
- **Conclusion**: HgCl₂ is **linear**.

### Final Conclusion
The linear species among the given compounds are **BeCl₂ and HgCl₂**.

### Summary of Linear Species
- Linear: BeCl₂, HgCl₂
- Not Linear: SO₂, O₃, H₂O