The dipole moment of a molecule depends on the difference in electronegativity between atoms and the molecular geometry.
1. Step 1: Analyze each molecule's dipole moment. - NH (Ammonia): This molecule has a pyramidal shape due to the lone pair on nitrogen, with a significant dipole moment because nitrogen is highly electronegative and the lone pair pushes the bond pairs. - NF (Nitrogen trifluoride): Although it has a similar structure to NH , the dipole moment of NF is lower because fluorine is highly electronegative, but the molecule has a more symmetrical shape that partially cancels the dipole. - H S (Hydrogen sulfide): The molecule has a bent shape, but sulfur’s electronegativity is lower than oxygen, and thus the dipole moment is smaller than that of NH . - CHCl (Dichloromethane): This molecule has a tetrahedral shape and chlorine is highly electronegative, which would result in a moderate dipole moment. However, the dipole moment is lower than that of NH and NF because the structure of CHCl is more symmetric. Thus, the correct order of dipole moments is NH > NF > H S > CHCl .