Nucleophilic Substitution

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Nucleophilic Substitution
Samantha Gutierrez

Nucleophilic Substitution
Introduction:
The purpose of this lab is to investigate how different factors affect the rate of SN1 and SN2 reactions. SN2 reactions proceed via a one step mechanism in which the incoming nucleophile attacks the electrophilic carbon center from the opposite side of the leaving group. This reaction mechanism implies that the stereochemistry of a chiral center will be inverted. SN1 reactions proceed via two steps, slow dissociation of the C-X bonds to form an intermediate carbocation and a fast second step in which the C-Nucleophile bond is formed. Since the intermediate carbocation is trigonal planar, the nucleophile can attack with equal probability from
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In the other test tube, 0.5mL of 0.2 M 2-chloro-2-methylpropane was added. At the same time, 1mL of 1.0 M AgNO3 in absolute ethanol was added to each test tube. Observations were recorded and rates of reactions were compared.
1mL of AgNO3 was added to one test tube. 0.5mL of AgNO3 and 0.5mL of ethanol was added to another test tube. At the same time, 1mL of 1.0 M 2-chloro-2-methylpropane was added to each test tube. Observations were recorded and rates to the two reactions were compared.
Results:
The reactions that we were specifically looking at in this lab were:
R-X + NaI → R-I + NaX AgNO3
R-X + CH3CH2OH → R-OCH2CH3 + AgX + H+ + NO3-

When 1-bromobutane, 2-bromobutane, and 2-methyl-2-bromobutane were added to 15% NaI solution, we observed cloudy with precipitants, clear with small precipitants, and a tint of yellow, respectively. When 1-bromobutane and 1-bromo-2-methylpropane were added to 15% NaI solution, we observed large precipitants and clear with small precipitants, respectively. When 1-bromobutane and 1-chlorobutane were added to 15% NaI solution, we observed small precipitants at first then large precipitants as time went on and a slight tint of yellow, respectively. When 1.0 M of 1-bromobutane and 2.0 M of 1-bromobutane were added to 15% NaI solution, we observed large precipitants with a fast reaction and small precipitants with a slower reaction time, respectively. When 7.5% NaI solution and 15%
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