Chem 210 - Exam #3 Sample

Sample Exams are designed to give you an idea of the types of questions you can expect.  Questions on these sample exams may not exactly agree with currently assigned material, so you may need to view other sample exams to see questions that might be similar to the upcoming exam. Answers for Sample Exam #3 are now available.

1. Give the structural formula for:

trans-3,4-dimethyl-3-hexene

(Z)-3-chloro-4-methyl-3-hexene

(S)-trans-4-methyl-2-hexene

2. Describe the pi double bond. Indicate which of the following compounds show geometric isomerism. Then, draw the isomeric structures, and specify each as being cis or trans or Z or E, as appropriate.

2-butene

1,2-dichloroethene

1-chloro-2-methyl-2-butene

3. When neopentyl alcohol, (CH₃)₃CCH₂OH, is heated with acid, it is slowly converted into an 85:15 mixture of two alkenes of formula C₅H₁₀. What are these alkenes, and how are they formed? Which one would you think is the major product, and why?

4. Give structures and names of the products (if any) expected from reaction of isobutylene with:

H₂, Ni --->

Br₂--->

I₂ --->

H₂SO₄ --->

H₂O, H+ --->

cold alkaline KMnO₄ --->

5. Name the following compounds using IUPAC (or accepted common names) nomenclature:

C=C-C-C-C=C

C=C-C-C-C

C=C-C=C-C=C

C-C=C-C-C-OH

      C-C
      |
C-C-C-C-C-Br
  |
  OH



C-C-C-C
    | |
   HO OH

C=C-Cl

6. Account for the fact that addition of CBrCl₃ in the presence of peroxides takes place faster with 2-ethyl-1-hexene than to 1-octene.

7. Define anti and syn addition. Give examples for the bromination of cis and trans 2-butene. What products will be obtained? Show the structure of a halonium ion.

8. Describe simple chemical tests that would distinguish between:

2-hexene and tert-butyl bromide

n-propyl alcohol and allyl alcohol (CH₂=CHCH₂OH)

sec-butyl alcohol and n-heptane

9. E2 elimination requires strong base, but E1 does not. Show the mechanism by which either type of elimination occurs.

10. Give the structure of the alkene you would start with, and the reagents and any special conditions necessary to convert it into each of these products:

t-butyl alcohol

isobutyl bromide

1-chloro-2-methyl-2-butanol

2,3-dimethyl-2,3-butanediol

11. Show the major alcohol or halide product for each of the following reactions:

C-C-C=C + HOH (acidic) ---->

C-C-C=C + HCl (aqueous) ---->

C-C-C=C + H₂SO₄ ---->

C-C-C=C + HBr (+peroxides) ---->

C-C-C=C + HBr (gas) ---->

12. Show reactions for either hydroboration or oxymercuration required to produce an alcohol. Be sure to include all required reactants, and the type of alcohol produced.

13. Show the major product of E2 or E1 elimination (dehydrohalogenation or dehydration) of:

3-bromo-2-methylpentane

4-bromo-2-methylpentane

C-C-C-C-C-Br

C-C-C-C-C
  |
  Br


  C
  |
C-C-C-C
  | |
  C Br


  C
  |
C-C-C-C
  | |
  C OH

EXTRA CREDIT (5 points): When treated with bromine and water, allyl bromide gives chiefly (80%) the primary alcohol, CH₂BrCHBrCH₂OH, in contrast to propylene, which gives the secondary alcohol, CH₃CHOHCH₂Br. Please give an explanation for this difference in orientation.