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1 | |
In nucleophilic substitution reactions with alkyl halides the leaving group is? |
| | A) | A hydroxide group. |
| | B) | A halide anion. |
| | C) | A halide cation. |
| | D) | A carbon atom. |
| | E) | An ester. |
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2 | |
Rank the following ions in terms of their leaving group reactivity.
Br-, Cl-, I-, F-. |
| | A) | Br- > Cl- > F- > I-. |
| | B) | I- > Br- > Cl- > F-. |
| | C) | Cl- > Br- > F- > I-. |
| | D) | F- > Cl- > Br- > I-. |
| | E) | F- > Cl- > Br- > I-. |
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3 | |
How are basicity and leaving group ability related? |
| | A) | They are not related to each other. |
| | B) | Good leaving groups are strong bases. |
| | C) | Good leaving groups are weak bases. |
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4 | |
The term SN2 stands for? |
| | A) | A solvation reaction. |
| | B) | An electrophilic addition reaction. |
| | C) | A nucleophilic reaction. |
| | D) | A unimolecular substituent reaction. |
| | E) | A bimolecular nucleophilic substitution reaction. |
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5 | |
The transition state geometry in an SN2 reaction is? |
| | A) | Trigonal planar. |
| | B) | Tetrahedral. |
| | C) | Pentagonal. |
| | D) | Trigonal bipyramidal. |
| | E) | Octahedral. |
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6 | |
The nucleophile in an SN2 reaction approaches the alkyl halide from? |
| | A) | Anywhere, is does not matter. |
| | B) | The same side of the carbon atom that the halide atom is attached to. |
| | C) | The backside of the carbon-halide bond. |
| | D) | The side of the carbon-halide bond. |
| | E) | The top of the carbon-halide bond. |
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7 | |
Which of the following compounds is least reactive in an SN2 reaction?
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| | A) | A |
| | B) | B |
| | C) | C |
| | D) | D |
| | E) | E |
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8 | |
The strength of a nucleophile depends on several factors, which statement is NOT true? |
| | A) | The anion is a stronger nucleophile than the neutral atom, or molecule. |
| | B) | More polarizable atoms are better nucleophiles. |
| | C) | The degree of solvation affects the nucleophilicity. |
| | D) | The connection between nucleophilicity and basicity holds across a row in the Periodic Table. |
| | E) | The connection between nucleophilicity and basicity holds down a column in the Periodic Table. |
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9 | |
The order of carbocation stability is? |
| | A) | 10 > 20 > 30 |
| | B) | 20 > 10 > 30 |
| | C) | 20 > 30 > 10 |
| | D) | 30 > 20 > 10 |
| | E) | 30 > 10 > 20 |
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10 | |
SN1 and SN2 reactions are? |
| | A) | both stereospecific |
| | B) | both stereoselective |
| | C) | stereoselective and stereospecific respectively |
| | D) | stereospecific and stereoselective respectively |
| | E) | neither stereospecific or stereoselective |
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11 | |
Which statement about carbocation rearrangements is false? |
| | A) | They are possible in SN1 reactions. |
| | B) | They are possible in SN2 reactions. |
| | C) | They normally involve the shift of a hydrogen atom. |
| | D) | They occur due to the greater stability of 30 carbocations. |
| | E) | They occur faster than intermolecular reactions. |
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12 | |
Which statement about the solvent effects on substitution reactions is false? |
| | A) | SN1 reactions are favored by polar solvents with a high dielectric. |
| | B) | SN2 reactions are favored by polar aprotic solvents. |
| | C) | 10 alkyl halides still react SN2 in polar solvents with a high dielectric. |
| | D) | 30 alkyl halides still react SN1 in non-polar solvents. |
| | E) | The stereoselectivity for 20 alkyl halides can
not be affected by the solvent. |
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13 | |
Which statement about competing elimination reactions is false? |
| | A) | Elimination is favored by nucleophiles which are also strong bases. |
| | B) | Elimination occur as the result of the loss of a proton adjacent to the leaving group. |
| | C) | Elimination occur only for SN2 reactions. |
| | D) | The structure of the alkyl halide can affect the amount of the elimination product. |
| | E) | The structure of the base can affect the amount of the elimination product. |
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14 | |
Which statement about substitution reactions with alcohols is true? |
| | A) | Substitution can be done directly on the alcohol. |
| | B) | Substitution always results in an inversion of configuration. |
| | C) | Substitution always results in a retention of configuration. |
| | D) | Substitution can only be done with hydrohalide acids. |
| | E) | Substitution is best achieved by first generating a better leaving group. |
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