Why is the dipole moment of SO2 1.63 D, but that of CO2 is 0 D? CO2 is linear, whereas SO2 is bent. The two polar bonds in CO2 are equal and in opposite directions, so they cancel each other out. CO2 must be dissolved in a nonpolar solvent in order to induce a dipole moment of 0 D. If under the same conditions, the dipole moments of SO2 and CO2 are identical. SO2 is symmetrical, whereas CO2 is not. Asymmetrical molecules always have a dipole moment of 0 D. SO2 must be dissolved in a polar solvent in order to induce a dipole moment. If under the same conditions, the dipole moments of SO2 and CO2 are identical.
The Correct Answer and Explanation is:
The dipole moment of SO₂ is 1.63 D, while that of CO₂ is 0 D, primarily due to differences in molecular geometry. CO₂ is a linear molecule with two identical polar C=O bonds oriented 180 degrees apart. This linear shape causes the bond dipoles to cancel each other out, resulting in a net dipole moment of zero. On the other hand, SO₂ has a bent molecular geometry due to the presence of a lone pair on the sulfur atom, which results in an angle of approximately 119 degrees between the S=O bonds. Because of this bent shape, the individual dipole moments of the S=O bonds do not cancel, and the molecule has a net dipole moment of 1.63 D.
The key difference lies in the symmetry of the molecules. In CO₂, the symmetrical linear shape means that even though each C=O bond is polar, their effects on the overall molecule cancel. This symmetry leads to a nonpolar molecule with no permanent dipole moment in the gas phase. SO₂, being bent, lacks this symmetry. The dipoles from each S=O bond combine vectorially to create a net dipole pointing away from the lone pair on the sulfur atom.
The polarity of a molecule is intrinsic and does not depend on the solvent it is dissolved in, although the solvent can influence properties like solubility and intermolecular interactions. The suggestion that a dipole moment can be induced by dissolving CO₂ or SO₂ in a certain type of solvent is not accurate in terms of changing their fundamental dipole moments. The dipole moment is determined by the electron distribution and shape of the molecule in its most stable geometry.
Therefore, SO₂ is polar due to its bent geometry, while CO₂ is nonpolar due to its linear, symmetrical geometry.
