7. Alkyl Halides and Nucleophilic Substitution

Question 1

A molecule containing a halogen atom bonded to the sp2 hybridized carbon of a carbon–carbon double bond.

Answer 1

Vinyl Halide

Question 2

A molecule such as C6H5X, containing a halogen atom X bonded to an aromatic ring.

Answer 2

Aryl Halide

Question 3

A molecule containing a halogen atom bonded to the carbon atom adjacent to a carbon–carbon double bond.

Answer 3

Allylic Halide

Question 4

A compound such as C6H5CH2X, containing a halogen atom X bonded to a carbon that is bonded to a benzene ring.

Answer 4

Benzylic Halide

Question 5

Synthetic alkyl halides having the general molecular formula CFxCl4 − x. Chlorofluorocarbons, abbreviated as CFCs, were used as refrigerants and aerosol propellants and contribute to the destruction of the ozone layer.

Answer 5

Chlorofluorocarbons

Question 6

Chlorofluorocarbons consisting of simple halogen-containing organic compounds that were once commonly used as refrigerants.

Answer 6

Freons

Question 7

An atom or group of atoms (Z) that is able to accept the electron density of the C–Z bond during a substitution or elimination reaction.

Answer 7

Leaving Group

Question 8

An electron-rich compound, symbolized by :Nu−, which donates a pair of electrons to an electron-deficient compound, forming a covalent bond. Lewis bases are nucleophiles.

Answer 8

Nucleophile

Question 9

A reaction in which a nucleophile replaces the leaving group in a molecule.

Answer 9

Nucleophilic Substitution

Question 10

A measure of how readily a leaving group (Z) can accept the electron density of the C–Z bond during a substitution or elimination reaction.

Answer 10

Leaving Group Ability

Question 11

A measure of how readily an atom donates an electron pair to other atoms.

Answer 11

Nucleophilicity

Question 12

A base that is a poor nucleophile due to steric hindrance resulting from the presence of bulky groups.

Answer 12

Nonnucleophilic Base

Question 13

A polar solvent that is capable of intermolecular hydrogen bonding because it contains an O─H or N─H bond.

Answer 13

Polar Protic Solvent

Question 14

A polar solvent that is incapable of intermolecular hydrogen bonding because it does not contain an O─H or N─H bond.

Answer 14

Polar Aprotic Solvent

Question 15

A rate equation in which the reaction rate depends on the concentration of two reactants.

Answer 15

Second-Order Rate Equation

Question 16

A reaction in which the concentration of both reactants affects the reaction rate and both terms appear in the rate equation. In a bimolecular reaction, two reactants are involved in the only step or the rate-determining step.

Answer 16

Bimolecular Reaction

Question 17

A rate equation in which the reaction rate depends on the concentration of only one reactant.

Answer 17

First-Order Rate Reaction

Question 18

A nucleophilic substitution mechanism that goes by a one-step concerted process, where both reactants are involved in the transition state. SN2 is an abbreviation for “Substitution Nucleophilic Bimolecular.”

Answer 18

SN2 Mechanism

Question 19

A nucleophilic substitution mechanism that goes by a two-step process involving a carbocation intermediate. SN1 is an abbreviation for “Substitution Nucleophilic Unimolecular.”

Answer 19

SN1 Mechanism

Question 20

A reaction that has only one reactant involved in the rate-determining step, so the concentration of only one reactant appears in the rate equation.

Answer 20

Unimolecular Reaction

Question 21

A reaction in which all bond forming and bond breaking occurs in one step.

Answer 21

Concerted Reaction

Question 22

Approach of a nucleophile from the same side as the leaving group.

Answer 22

Frontside Attack

Question 23

Approach of a nucleophile from the side opposite the leaving group.

Answer 23

Backside Attack

Question 24

The same relative stereochemistry of a stereogenic center in the reactant and the product of a chemical reaction.

Answer 24

Retention of Configuration

Question 25

The opposite relative stereochemistry of a stereogenic center in the starting material and product of a chemical reaction. In a nucleophilic substitution reaction, inversion results when the nucleophile and leaving group are in the opposite position relative to the three other groups on carbon.

Answer 25

Inversion of Configuration

Question 26

The inversion of a stereogenic center involved in an SN2 reaction.

Answer 26

Walden Inversion

Question 27

The formation of equal amounts of two enantiomers from an enantiomerically pure starting material.

Answer 27

Racemization

Question 28

A positively charged carbon atom. A carbocation is sp2 hybridized and trigonal planar, and contains a vacant p orbital.

Answer 28

Carbocation

Question 29

A carbocation having the general structure RCH2+.

Answer 29

Primary (1°) carbocation

Question 30

A carbocation having the general structure R2CH+.

Answer 30

Secondary (2°) carbocation

Question 31

A carbocation having the general structure R3C+.

Answer 31

Tertiary (3°) carbocation

Question 32

An inductive effect in which a nearby electronegative atom pulls electron density toward itself through σ bonds.

Answer 32

Electron-withdrawing inductive effect

Question 33

The overlap of an empty p orbital with an adjacent σ bond.

Answer 33

Hyperconjugation

Question 34

A postulate that states that the transition state of a reaction resembles the structure of the species (reactant or product) to which it is closer in energy.

Answer 34

Hammond postulate

Question 35

A PO43− anion.

Answer 35

Phosphate

Question 36

A good leaving group that is often used in biological systems. Diphosphate (P2O74−) is abbreviated as PPi.

Answer 36

Diphosphate

Question 37

A good leaving group used in biological systems. Triphosphate (P3O105−) is abbreviated as PPPi.

Answer 37

Triphosphate

Question 38

A reaction in which a CH3 group is transferred from one compound to another.

Answer 38

Methylation

Question 39

A compound isolated from a natural source.

Answer 39

Natural Product