NTA Abhyas NEET2020ChemistryChemical Bonding and Molecular StructurePractice
Which one of the following arrangement of molecules is correct on the basis of their dipole moments?
Options
- AB F 3 > N H 3 > N F 3
- BB F 3 > N F 3 > N H 3
- CN H 3 > B F 3 > N F 3
- DN H 3 > N F 3 > B F 3
Correct answer
D. N H 3 > N F 3 > B F 3
Step-by-step solution
Both N F 3 and N H 3 have identical shape (pyramidal) and a lone pair of electron on nitrogen. Dipole moment of N H 3 is higher than N F 3 molecule as the orbital moment due to lone pair of electrons and the resultant dipole moment of 3 N-F bonds point in the opposite directions to that of lone pair of electrons. B F 3 is a symmetrical molecule. It has zero dipole moment.