Question

Which of the following molecule does not possess a permanent dipole moment?

• A. H₂S
• B. SO₂
• C. CS₂
• D. NH₃

Answer 1

Answer: (C)

CS₂

Answer 2

A molecule has zero dipole moment if its geometry is symmetrical, causing individual bond dipoles to cancel out. CS₂ (S=C=S) has a linear geometry. Although C=S bonds are polar, their dipoles are equal and opposite, resulting in a net dipole moment of zero. H₂S, SO₂, and NH₃ have bent or pyramidal geometries, leading to non-zero dipole moments.