Multiple Choice
Which of the following molecules has no net dipole moment?
1
views
13. Liquids, Solids & Intermolecular Forces
Molecular Polarity
Struggling with General Chemistry?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Is the molecule BF_3 polar or nonpolar?
A
BF_3 is nonpolar because boron and fluorine have the same electronegativity.
B
BF_3 is polar because it contains three fluorine atoms.
C
BF_3 is polar because the B–F bonds are polar and the molecule has a net dipole moment.
D
BF_3 is nonpolar because its molecular geometry is trigonal planar and the dipoles cancel out.
Verified step by step guidance1
Identify the molecular geometry of BF\_3. Since boron is the central atom bonded to three fluorine atoms with no lone pairs, the shape is trigonal planar.
Recall that in a trigonal planar molecule, the bond angles are approximately 120\degree, and the atoms are symmetrically arranged around the central atom.
Consider the polarity of each B–F bond. Because fluorine is more electronegative than boron, each B–F bond is polar with a dipole moment pointing from boron to fluorine.
Analyze the vector sum of the three bond dipoles. Due to the symmetrical trigonal planar shape, the three dipole moments are equally spaced and cancel each other out.
Conclude that since the individual bond dipoles cancel, the molecule has no net dipole moment and is therefore nonpolar.
Related Videos
Related Practice
Molecular Polarity practice set
Problem sets built by lead tutorsExpert video explanations