Which of the following molecules is linear ?

Options

A. `Icl_(2)^(-)`
B. `SO_(3)^(2-)`
C. `SO_(3)`
D. `SO_(2)`

Explanation

To determine which of the given molecules is linear, we will analyze the molecular geometry and hybridization of each molecule mentioned in the video transcript.

### Step-by-Step Solution:

1. **Identify the Molecules**: The molecules mentioned are ICl2^-, SO3^2-, SO3, and SO2. We will analyze each of these to determine their shapes.

2. **Analyze ICl2^-**:
- **Valence Electrons**: Iodine (I) has 7 valence electrons, and each chlorine (Cl) has 7 valence electrons. The negative charge indicates an extra electron.
- **Total Valence Electrons**: 7 (I) + 2*7 (Cl) + 1 (extra electron) = 22 electrons.
- **Lewis Structure**: Iodine is the central atom with two chlorine atoms bonded to it and three lone pairs of electrons.
- **Steric Number**: 2 (sigma bonds) + 3 (lone pairs) = 5.
- **Hybridization**: sp^3d.
- **Molecular Geometry**: The geometry is trigonal bipyramidal, but the shape is linear due to the arrangement of the lone pairs.

3. **Analyze SO3^2-**:
- **Valence Electrons**: Sulfur (S) has 6 valence electrons, and each oxygen (O) has 6 valence electrons. The 2 negative charges contribute 2 extra electrons.
- **Total Valence Electrons**: 6 (S) + 3*6 (O) + 2 (extra electrons) = 32 electrons.
- **Lewis Structure**: Sulfur is the central atom with three oxygen atoms bonded to it and one lone pair.
- **Steric Number**: 3 (sigma bonds) + 1 (lone pair) = 4.
- **Hybridization**: sp^3.
- **Molecular Geometry**: The shape is trigonal pyramidal.

4. **Analyze SO3**:
- **Valence Electrons**: Sulfur has 6 valence electrons, and each oxygen has 6 valence electrons.
- **Total Valence Electrons**: 6 (S) + 3*6 (O) = 24 electrons.
- **Lewis Structure**: Sulfur is the central atom with three oxygen atoms bonded to it and no lone pairs.
- **Steric Number**: 3 (sigma bonds) + 0 (lone pairs) = 3.
- **Hybridization**: sp^2.
- **Molecular Geometry**: The shape is trigonal planar.

5. **Analyze SO2**:
- **Valence Electrons**: Sulfur has 6 valence electrons, and each oxygen has 6 valence electrons.
- **Total Valence Electrons**: 6 (S) + 2*6 (O) = 18 electrons.
- **Lewis Structure**: Sulfur is the central atom with two oxygen atoms bonded to it and one lone pair.
- **Steric Number**: 2 (sigma bonds) + 1 (lone pair) = 3.
- **Hybridization**: sp^2.
- **Molecular Geometry**: The shape is bent due to the lone pair.

6. **Conclusion**: Among the analyzed molecules, **ICl2^-** is the only molecule that has a linear shape.

### Final Answer:
The linear molecule is **ICl2^-**.