Which of the following molecules has a zero dipole moment?

Step-by-step solution

Dipole moment is a vector quantity and depends on the molecular geometry. In BeF ₂ , the central beryllium atom has no lone pairs and forms two sigma bonds. It has a linear geometry. The two Be-F bond dipoles are equal and point in opposite directions, cancelling each other out to give a net zero dipole moment. H ₂ O has a bent shape due to two lone pairs on oxygen, so its bond dipoles do not cancel. NH ₃ has a trigonal pyramidal shape due to one lone pair on nitrogen, resulting in a non-zero net dipole moment. CH