Polarity in a molecule and hence the dipole moment depends primarily on electronegativity of the constituent atoms and shape of a molecule. Which of the following has the highest dipole moment? A `CO_(2)` B HI C `H_(2)O` D `SO_(2)`

Options

A. `CO_(2)`
B. HI
C. `H_(2)O`
D. `SO_(2)`

Explanation

To determine which molecule has the highest dipole moment among CO₂, HI, H₂O, and SO₂, we will analyze the molecular structure and electronegativity of the constituent atoms step by step.

### Step 1: Analyze the structure of CO₂
- **Structure**: Carbon dioxide (CO₂) has a linear structure with the carbon atom in the center and two oxygen atoms on either side.
- **Polarity**: The dipole moments of the two C=O bonds are equal in magnitude but opposite in direction, which cancels each other out.
- **Dipole Moment**: Therefore, the net dipole moment (μ) of CO₂ is 0.

**Hint**: Remember that in linear molecules, if the dipole moments are equal and opposite, they cancel each other out.

### Step 2: Analyze the structure of HI
- **Structure**: Hydrogen iodide (HI) is a diatomic molecule.
- **Polarity**: The bond between hydrogen and iodine is polar because iodine is more electronegative than hydrogen.
- **Dipole Moment**: Since HI has a single bond and is not symmetrical, it has a non-zero dipole moment.

**Hint**: For diatomic molecules, the dipole moment is determined by the difference in electronegativity between the two atoms.

### Step 3: Analyze the structure of H₂O
- **Structure**: Water (H₂O) has a bent molecular geometry due to the two lone pairs on the oxygen atom.
- **Polarity**: The O-H bonds are polar, and the bent shape means that the dipole moments do not cancel out.
- **Dipole Moment**: The net dipole moment of H₂O is significant and directed towards the oxygen atom.

**Hint**: Bent shapes often lead to a net dipole moment because the bond dipoles do not cancel out.

### Step 4: Analyze the structure of SO₂
- **Structure**: Sulfur dioxide (SO₂) also has a bent shape due to the presence of a lone pair on the sulfur atom.
- **Polarity**: The S=O bonds are polar, and similar to H₂O, the bent shape means the dipole moments do not cancel.
- **Dipole Moment**: SO₂ has a net dipole moment directed towards the oxygen atoms.

**Hint**: Like H₂O, the bent shape of SO₂ contributes to a significant net dipole moment.

### Step 5: Compare the dipole moments
- **CO₂**: μ = 0 (linear and symmetric)
- **HI**: μ > 0 (polar but diatomic)
- **H₂O**: μ > 0 (bent and significant dipole)
- **SO₂**: μ > 0 (bent and significant dipole)

Among these, H₂O and SO₂ have significant dipole moments due to their bent shapes, while HI has a smaller dipole moment as it is a diatomic molecule. However, H₂O has a greater dipole moment than SO₂ due to the higher electronegativity difference between H and O compared to S and O.

### Conclusion
The molecule with the highest dipole moment among the options provided is **H₂O**.

**Final Answer**: C) H₂O