Kinetic Study of a Solvolysis Lab

924 words 4 pages
Kinetic study of a Solvolysis (Sn1) Reaction

Aneadra Bowles
Adasia Rutledge
Krystal Flakes
Robert Grimes
Jasmine Ross

June 5, 2012

Purpose: The purpose of this experiment is to use kinetics to study a solvolyis reaction
Introduction: The purpose of this experiment is to understand the kinetics of the hydrolysis of t-butyl chloride.The kinetic order of reaction was studied under the effects of variations in temperature, solvent polarity, and structure. It is particularly observed in tertiarhalides i.e. in SN1mechanism, Nucleophilic Substitution which is in 1storder. It is basically a reaction that involves substitution by a solvent that pretendslikea nucleophile i.e. it donates electrons. The reaction being in firstorder means
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A form of titration was implimented to show the formation of HCl and from that data we were able to construct a graph and, using the slope, determine the rate constant of the reaction.
We also used observed how a more polar solvent affects the rate of reaction. The first solvent that we used was 50/50 water to ethanol. The second solvent; however, was a 60/40 mixture of water to ethanol. Because water is a polar molecule the second solvent was more polar than the first and thus more able to stabilize the formation of the carbocation intermediate in the reaction. This stabilization meant less energy was needed to reach the carbocation intermediate and since formation of the carbocation is the rate determining step in an SN1 reaction the reaction could therefore proceed at a faster rate compared to the first.
The graphs of the two reactions confirm this because the reaction that had the more polar second solvent resulted in a rate constant that was higher than the first reaction. The only way that the solvent could have affected the reaction rate is if a carbocation intermediate was formed. The polar solvent could then stabilize it and increase the rate of reaction just as the SN1 reaction mechanism predicts.
One possible source of error in this experiment could have been that we did not record the times at the exact point that the solution turned acidic. This would have given data to support a slower reaction (albeit not