NCl3 Is Polar Because NCl3 would have N as the central atom, then three Cl atoms would be spread around it. Lastly, there would be one lone pair of electrons attached to the central atom. It would look like ammonia in terms of molecular geometry - a trigonal pyramidal molecule (shaped like a tripod)
SO3 is non polar because the dipoles "cancel out".
PCl5 is non polar. This is due to the molecule structure of Pcl5. All the bonds cancel out each other. This is what makes it non polar since there are no net dipole.
So, That Means The Ans of this Question Is : (D)
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Akshay Meena,
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M.Tech, IIT Kharagpur