Chapter 2.1B, Problem 2.3P

For each of the following compounds

1. 1. Draw the Lewis structure.
2. 2. Show how the bond dipole moments (and those of any nonbonding pairs of electrons) contribute to the molecular dipole moment.
3. 3. Estimate whether the compound will have a large small, or zero dipole moment.
4. a. NH₄⁺
5. b. O₃
6. a. NH₄⁺ has four polar N—H bonds These bonds are probably more polarized than a typical N—H bond, because the N in NH₄⁺ bears a formal positive cha^rge Nevertheless, these four colar bonds have a symmetric tetrahedral arrangement so they cancel each other.

1. b. Ozone (O₃) is an sp² hybrid structure with a lone pair on the central oxygen atom Therefore O₃ must be bent. The resonance structures imply partia negatve charges on the outer oxygens and a partial positive charge on the central oxygen. The lone pair on the central oxygen cancels part, but not all, of the vector sum of the two O—O dipoles The resulting not d polo is relatively small.

1. a. Ozone (O₃) is an sp² hybrid structure, with a lone pair on the central oxygon atom Therefore, O₃ must be bent. The resonance structures imply partial negative charges on the outer oxygens end a partial positive charge on the central oxygen. The lone pair on the central oxygen cancels part but not all, of the vector sum of the two O—O dipoles The resulting net dipole is relatively small.

1. b. CH₂CI₂
2. c. CH₃F
3. d. CF₄
4. e. CH₃OH
5. f. HCN
6. g. CH₃CHO
7. h. H₂C=NH
8. i. (CH₃)₃N
9. j. CH₂=CHCI
10. k. BF₃
11. l. BeCl₂