| Qu 1 |
Use the following list of compounds to answer the questions below: |
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Select the compound that is best described as: |
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(a) A neutral, 4 p-electron, anti-aromatic
system. |
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(b) A 6 p-electron, aromatic system. |
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(c) An aromatic system because n=2 in the Huckel 4n+2 rule. |
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(d) A non-aromatic, conjugated 6 p-electron
system |
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(e) A non conjugated hydrocarbon. |
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(f) Non-aromatic as drawn, but if H- were removed would give an aromatic
cation. |
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(g) Non-aromatic as drawn, but has an important resonance structure
that is aromatic. |
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(h) Non-aromatic as drawn but has an aromatic conjugate base. |
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| Qu 2: |
Consider the pKa data for the following aromatic N containing systems: |
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Henderson-Hasselbach equation: pKa = pH +
log ([A-]/[HA]) |
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Based on the scheme provided, |
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(a) Which species is the strongest acid? |
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(b) At pH=4.2, what is the relative ratio of pyridine to its conjugate acid? |
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(c) Which is the better base: pyridine or aniline, and why? |
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(d) Why is pyrrole is a weaker base than pyridine? |
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| Qu 3: |
Rate the resonance energies (in comparison to one another) of each
of the following: |
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| Qu 4: |
Rate the relative stability of the following carbocations (in comparison
to one another): |
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| Qu 5: |
Use the following data to answer the questions below: |
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(a) Calculate the resonance energy of anthracene.  |
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(b) Anthracene is known to react with maleic anhydride in a Diels-Alder
reaction. Predict which of the products shown is obtained. Why ?
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