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Topic: Kinetics of Nucleophilic Substitutions  (Read 5532 times)

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Offline suRe_Panda

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Kinetics of Nucleophilic Substitutions
« on: February 11, 2009, 10:17:05 PM »
1. The ability for a reaction to proceed quickly by SN1 or SN2 mechanisms often depends on the
solvent used, and we group solvents into 3 general categories: apolar, polar aprotic and
polar protic. How can each of these types of solvents help or hinder an SN2 reaction involving
a neutral nucleophile (such as NH3) with a primary alkyl halide (such as PhCH2Br)?
2. In an SN1 reaction involving a chiral alkyl halide, such as 2R-chloro-2-phenylbutane, there is
racemization, but most often more inversion than retention. Why?
3. The experimental procedure does not actually measure the rate of product formation. What
does the colour change actually measure? Does this procedure discriminate between SN1
and E1 paths? Explain.
4. In your plot to calculate Ea, what does the y-intercept represent?
5. How can equation 6 be transformed to equation 7 (page 25)?


If anyone can provide some help with these questions it would be greatly appreciated.

Offline azmanam

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Re: Kinetics of Nucleophilic Substitutions
« Reply #1 on: February 11, 2009, 10:26:15 PM »
what are your thoughts?
Knowing why you got a question wrong is better than knowing that you got a question right.

Offline suRe_Panda

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Re: Kinetics of Nucleophilic Substitutions
« Reply #2 on: February 11, 2009, 10:31:26 PM »
I have no idea, which is why i ask =)

Offline Telamond

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Re: Kinetics of Nucleophilic Substitutions
« Reply #3 on: February 12, 2009, 01:41:07 AM »
1. The ability for a reaction to proceed quickly by SN1 or SN2 mechanisms often depends on the
solvent used, and we group solvents into 3 general categories: apolar, polar aprotic and
polar protic. How can each of these types of solvents help or hinder an SN2 reaction involving
a neutral nucleophile (such as NH3) with a primary alkyl halide (such as PhCH2Br)?
2. In an SN1 reaction involving a chiral alkyl halide, such as 2R-chloro-2-phenylbutane, there is
racemization, but most often more inversion than retention. Why?
3. The experimental procedure does not actually measure the rate of product formation. What
does the colour change actually measure? Does this procedure discriminate between SN1
and E1 paths? Explain.
4. In your plot to calculate Ea, what does the y-intercept represent?
5. How can equation 6 be transformed to equation 7 (page 25)?

1. Look up solvent effects in your course book.
2. Draw the structure of 2R-chloro-2-phenylbutane, also, draw out the intermediate.
3. What experiment?
4. Google -> Arrhenius Equation, should have the answer to this question.
5. Which equation?

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