Here's why:
* Molecular geometry: SO2 has a bent molecular geometry due to the presence of two lone pairs of electrons on the sulfur atom.
* Polar bonds: The sulfur-oxygen bonds are polar because oxygen is more electronegative than sulfur, creating a partial negative charge on the oxygen atoms and a partial positive charge on the sulfur atom.
* Vector addition: The two polar bonds create individual dipole moments that point towards the oxygen atoms. These dipole moments do not cancel each other out because of the bent geometry. Instead, they add up vectorially to form a net dipole moment that is also pointing towards the oxygen atoms.
Therefore, the net dipole moment of SO2 is non-zero and points towards the oxygen atoms, making it a polar molecule.
