Multiple Choice
If you want a molecule that is highly polar, look for one that contains:
13. Liquids, Solids & Intermolecular Forces
Molecular Polarity
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Which of the following best describes the molecular polarity of the perchlorate ion, ClO_4^-?
A
ClO_4^- is a nonpolar ion because its molecular geometry is tetrahedral and the charge is evenly distributed.
B
ClO_4^- is nonpolar because it has a linear geometry.
C
ClO_4^- is a polar ion due to the presence of a lone pair on the chlorine atom.
D
ClO_4^- is a polar ion because it contains polar Cl–O bonds.
Verified step by step guidance1
Step 1: Determine the Lewis structure of the perchlorate ion, ClO_4^-. Identify the central atom (Cl) and the surrounding atoms (four O atoms), and account for the overall charge (-1) when distributing electrons.
Step 2: Analyze the molecular geometry of ClO_4^- using VSEPR theory. With four oxygen atoms bonded to chlorine and no lone pairs on the central atom, the geometry is tetrahedral.
Step 3: Consider the polarity of individual Cl–O bonds. Since Cl and O have different electronegativities, each Cl–O bond is polar.
Step 4: Evaluate the symmetry of the molecule. In a tetrahedral geometry with identical surrounding atoms, the bond dipoles cancel out due to symmetrical charge distribution.
Step 5: Conclude that because the molecular geometry is tetrahedral and symmetrical, the overall ion is nonpolar despite having polar bonds, and the negative charge is evenly distributed.
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Molecular Polarity practice set
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