Answer
See the explanation
Work Step by Step
To determine which molecules have net dipole moments (i.e., are polar), we need to consider both molecular geometry and electronegativity differences.
Polar Molecules (Have Net Dipole Moments):
1) SeO₂ (Selenium dioxide)
Shape: Bent
Reason: Asymmetrical shape with polar Se–O bonds → net dipole moment
2) PCl₃ (Phosphorus trichloride)
Shape: Trigonal pyramidal
Reason: Lone pair on P causes asymmetry → net dipole moment
3) SCl₂ (Sulfur dichloride)
Shape: Bent
Reason: Lone pairs on S and polar S–Cl bonds → net dipole moment
Nonpolar Molecules (No Net Dipole Moment):
1) SeO₃ (Selenium trioxide)
Shape: Trigonal planar
Reason: Symmetrical geometry cancels dipoles → no net dipole
2) SiF₄ (Silicon tetrafluoride)
Shape: Tetrahedral
Reason: Symmetrical geometry with identical Si–F bonds → no net dipole
