Solution

$CCl_4$, $CO_2$ and $BF_3$ are all symmetric molecules with zero net dipole moment due to cancellation of bond dipoles. HI is a polar diatomic molecule with a non-zero dipole moment ($\mu=0.38$ D) due to the electronegativity difference between H and I.

Concept Dipole moment and molecular geometry

Chemical Bonding and Molecular Structure in past papers

108 questions from this chapter have appeared across 27 exam years.