Of the following molecules, only __ is polar.
A) CCl4
B) BCl3
C) NCl3
D) BeCl2
E) Cl2
3 Answers
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Think about the geometry. Each of the bonds here is polar (except for Cl2), so the molecular dipole moment depends whether or not each of the bond dipoles cancels with the other bond dipoles in the molecule. Think about symmetry. If you’re having trouble visualizing it, use a model kit.
a) tetrahedral, all bond dipoles cancel
b)trigonal planar, all bond dipoles cancel
c) trigonal pyramidal BOND DIPOLES DO NOT CANCEL
d)linear, all bond dipoles cancel
e) no polar bonds… both atoms are equally electro negative.
Source(s): Chemist -
answer C is polar because it has a trigonal pyramidal shape with C at the top and the 3 Cls at the base vertices.
Cl2 can’t be polar—covalent diatomic molecule with no charge assymetry
BeCl2 is planar–Be in center with Cls at 180 degrees on either side
BCl3 is trigonal planar—B in center with Cls at 120 degrees surrounding
CCl4—C is surrounded by the 4 Cls in a tetrahedral structure
Source(s): Ph. D. Chem Engr + chem tutor for several years + -
Because of its shape, NCl3 is the only molecule that is polar.
