practice_exam_Practice Exam_1-1 KEY - 1 Rank the fo llowing...

Unformatted text preview: 1. Rank the fo llowing co mpounds in order of increasing basicit y (1 = least basic): N N O 2 3 1 2. Ethynylestradio l (drawn below) is the active component of birth control pills. a. Identify the hybridizat ion of the atoms indicated by the arrows. b. Identify the two most acidic sites in the ent ire mo lecule. Mark the most acidic site with the number 1, and the second most acidic site with the number 2. Provide a brief explanation for your ranking. 2 HO s p 1 HO s p3 s p3 s p2 Explanat ion: The OH bonds will be the most acidic, because the electronegat ive oxygen atoms are best able to stabilize the negative charge in the conjugate base. The conjugate base fro m deprotonation of the OH group on the left is stabilized by several resonance structures, the one on the right is not. 3. Draw Lewis structures for B(OH)3 and BF3. Draw the most important resonance structure for each compound. H O B O H O H O H H O B O H F B F F F F B F B(OH) 3 resonance structure B F 3 resonance structure Which co mpound will be the stronger Lewis acid? Briefly explain why. BF3 is the stronger Lewis acid because the F atoms are more electronegative, and therefore more effect ive in removing charge fro m the B, making it a better acceptor of electron pairs. 4. Fill in the boxes with the appropriate reagents and/or products. B r 2 Br Br SOCl 2 OH Cl OH HBr Br 5. Draw Newman pro ject ions of all staggered conformations of 1,2­dichloroethane. Rank them in order of stabilit y (1 = most stable). Rank them in order of polarit y (1 = least polar). H H Cl H Cl H H Cl Cl H H H Cl Cl H H H H these last two are identical most stable = 1 least polar = 1 less stable = 2 more polar = 2 less stable = 2 more polar = 2 6. Name these co mpounds according to IUPAC rules: I Cl OH CH 3 3­chloro­2,3­dimethyl­2­butano l 1­iodo­2­methylcyclopentane 3­ethylbic yclo[4.1.0]heptane 7. Rank these co mpounds in order of increasing boiling point (1 = lowest boiling): O H F 1 3 2 8. Draw a clear 3­dimensio nal representation of the most stable conformat ion of each of the fo llo wing co mpounds cis­1­iodo­3­methylcyclobutane trans­1­isopropyl­3­methylcyclohexane CH 3 I CH 3 H C 3 CH 3 ...
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