Cliffs AP Chemistry, 3rd Edition

In the benzene molecule, there are 9 single bonds (9σ) and 3 double bonds (3σand 3π) for a
total of 12 sigma bonds.

8. Which one of the following does NOT exhibit resonance?

A. SO 2

B. SO 3

C. HI

D. CO 3 2-

E. NO 3 -

Answer: C

There are no alternative ways of positioning electrons around the HI molecule. If you missed
this question, refer to your textbook on the concept of resonance.

Note: Had you been given the choice, CH 3 Br, you would not choose it due to a possible

Baker-Nathan effect (no-bond resonance). In base, one result is protolysis:

9. What type of hybridization would you expect to find in BCl 3?

A. sp

B. sp^2

C. sp^3

D. sp^3 d^2

E. No hybridization occurs in this molecule.

Br

−

H

+

+

H

H

C H Br

H

H

C

H H

H

H H

H

C

C

C C

C

C

Part II: Specific Topics