Is it true that the dipole moment of sulphur dioxide is zero?

No. Only diatomic molecules like H2 or O2 have no dipole moment. The dipole moment is related to the electronegativity of an atom. Because the electronegativities of sulfur (2.58) and oxygen (3.44) are not the same, the electrons are not shared equally in the sulfur dioxide molecule. read more

The dipole moment of CO2 is not always zero, otherwise it could not have infrared absorbtion and act as a greenhouse gas. When the molecule vibrates, e.g. the carbon “bounces” between the two oxygens, or the carbon-oxygen bonds bend, so that the molecule is no longer linear, it acquires a dipole moment. read more

No. Sulphur dioxide do not have zero dipole moment. The dipole moment would have 0 if the structure of the sulphur dioxide is linear as of C02. As Sulphur dioxide has a lone pair therefore it surely has a non-zero net dipole moment. read more