Question

Which one of the following molecules is polar? Showallworkindetails. A) BH3 B) CCl4 C) SO2 D) CO2 E) PF5

Answer 1

Answer:

C) SO₂  

Explanation:

The figure below shows — clockwise from the upper left — BH₃, CCl₄, SO₂. CO₂, and PCl₅.

You must draw the Lewis structures of the molecules and then use VSEPR theory to figure out their molecular shape.

A) BH₃

BH₃ has a trigonal planar geometry.

It is nonpolar because of symmetry.

The bond dipole of the vertical B-H bond balances the equal and opposite resultant of the two downward-pointing B-H bonds.

BH₃ is nonpolar.

B) CCl₄

CCl₄ has a tetrahedral geometry.

The resultant of the two C-Cl bond dipoles on the right balances the equal and opposite resultant of the two C-Cl bond dipoles on the right.

CCl₄ is nonpolar.

C) SO₂

The Lewis structure shows that the central S atom has two S=O double bonds and a lone pair.

The electron pair geometry is trigonal planar and the molecular geometry is bent.

There is a net resultant of the S=O bond dipoles.

SO₂ is polar.

D) CO₂

CO₂ has a linear geometry with two C=O bonds pointing in opposite directions.

The bond dipoles cancel, so

CO₂ is nonpolar.

E) PCl₅

PCl₅ has a trigonal bipyramidal geometry.

The axial P-Cl bond dipoles cancel, as do the equatorial trigonal planar ones.

PCl₅ is nonpolar.