TPR question about solvents

[Melomare17]

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Can someone explain the answer to this:

Which one of the following would be the best solvent for the addition of HCl to 3-hexene?

a. H2O
b. CH3OH
c. CH3CO2H
d. 3-Hexene

answer is D

 

[SaintJude]

Well, I think this TPR question is stupid..But for what's it worth....

3-hexene is nonpolar and all the incorrect choices are polar. The point of a solvent is to choose a substance that will dissolve the solute. Like dissolves like so D is best choice.

 

[MedPR]

Solvents A-C would introduce worse leaving groups than Cl. Poor leaving group = not going to vacate the alkyl = Cl- won't get to stay on it.

 

[Melomare17]

oh ok thanks!

 

[pfaction]

Actually, I have no idea how this reaction even works. I would have thought that it went via Markovnikov addition straight, what's this about a solvent? What did you mean, MedPR?

 

[MedPR]

Can someone explain the answer to this:

Which one of the following would be the best solvent for the addition of HCl to 3-hexene?

a. H2O
b. CH3OH
c. CH3CO2H
d. 3-Hexene

answer is D

Actually, I have no idea how this reaction even works. I would have thought that it went via Markovnikov addition straight, what's this about a solvent? What did you mean, MedPR?

I look at all of these reactions in terms of nucleophile strength (even though this is an electrophlic addition) because my brain works through mechanisms the best if I start at that point.

However, I think the main reason why you don't use protic solvents for HX addition to an alkene is because polar solvent results in solvation of X- and, in the case of answers A-C, formation of better nucleophiles than Cl-. Hydroxide, methoxide, and acetate are all better nucleophiles than chloride.