1. (16 pts) Draw an accurate Lewis structure, on the line provided, for each of the molecules below. Please use lines to represent bonding electron pairs. Indicate all unshared electrons and formal charges.

3. (16 pts) Draw both chair conformations of cis-1-isopropyl-4-methylcyclohexane. Label all substituents (other than hydrogen) as axial (ax) or equatorial (eq). If one conformation is more stable than the other, circle it and, in one sentence, explain why.

4. (16 pts) Draw Newman projections of both the most stable and least stable conformations of 1,2-ethanediol.

5. (12 pts) The molecule drawn below is dimethisterone, a testosterone derivative. On each line, provide the hybridization of the indicated atoms.

7. (15 pts) Consider the four acetic acid derivatives in the box, along with the pKa values under each molecule.

b. How do you know?       It has the highest pKa value

c. Why is it the weakest acid?    It lacks any Cl atoms, which would withdraw electrons from the O-H bond via an inductive effect

d. Each acid above has an associated conjugate base. In the box, draw the structure of the second weakest conjugate base.

e. Using the weakest acid, draw appropriate resonance contributors to illustrate why its conjugate base is so stable:

f. What is the correlation between the strength of an acid and the stability of its conjugate base, and why does this correlation exist?

The more stable the conjugate base, the stronger the acid.  This is because loss of a proton leaves an anion, and the more stable this anion is on its own, the more likely the proton is to leave it.

Bonus (5 pts, no partial credit possible) Diazomethane, CH₂N₂, is a very useful but explosive reagent.  Draw two resonance contributors for this molecule.  (Hint:  The atoms are attached in the order C-N-N.)