Answer:
In SO2 , the bond angle is 119^∘ whereas in SO3 , the bond angle is 120^∘ .
Step-by-step explanation:
S atom in both SO2 and SO3 is sp^2-hybridized.
There are 3 bonding sets of electrons and one non-bonding pair on the sulphur. So the shape is based on a tetrahedral structure - but the extra repulsion of the non-bonding pair will decrease the O-S-O angles by a few degrees from the 'perfect' tetrahedral angle.
The bonding in SO3 can be described as a combination of 3 resonance forms of 1 double and 2 single bonds. The SO2 molecule has a dipole moment, The starting point of 109.5 degrees is only applicable for 4 electron regions round the central atom. In SO2, we have 2 double bonds and one lone pair ; 3 electron regions so the default angle is 120 degrees. The extra repulsion of the lp vs double bonds accounts for reduction to 119. S atom in both SO2 and SO3 is sp2-hybridized. But it is related to dipole moment and assertion is the explanation from bent angle so here reason is unable to give explanation of assertion.