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Good day, i had organic chemistry labs. And we had this reaction: $$\ce{(CH3)3COH + HCl -> (CH3)3CCl + H2O}$$

My question is: how do i explain my yield of reaction is only 40%?

My theory is: reaction is reversible so the K isn't so high and that lead to yield 40%. If my theory is right please explain me how to calculate K?

I had these informations:

V$\ce{((CH3)3COH)}$ = 10 ml

V$\ce{(HCl)}$ = 20 ml HCl was concentrated.

Thank for answers.

ron
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Matej
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  • Welcome to Chemistry.SE! To acquaint yourself with this page, take the tour and visit the help center. Furthermore this tutorial shows you how math and chemical formulae can be nicely formatted on this site. Finally, we have an important policy: your questions (especially homework questions), should show your own work or thinking that you have already done in an initial attempt to answer the question. – Philipp Nov 08 '14 at 16:28
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1 Answers1

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$\ce{H2O}$ is a very poor nucleophile and we are dealing with a tertiary substituted carbon, so we can minimize the scope of possible reaction mechanisms to the $\ce{E 1}$ and $\ce{S_{n}1}$ type mechanisms. $\ce{E 1}$ will compete here with $\ce{S_{n}1}$, forming tert-Butyl chloride and isobutylene respectively. That is probably where most of your loss is coming from. Other reasons can be indeed that a bit is left in the equilibrium, but I don't think that would be much since $\ce{H3O+}$ is a much better leaving group than $\ce{Cl-}$. Note that is chemistry papers the yield obtained is almost never a 100% of theory.

Jori
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