Substitution vs. Elimination

Each list begins with basic conceptual vocabulary you need to know for MCAT questions and proceeds to advanced terms that might appear in context in MCAT passages. The terms are links to Wikipedia articles.
The haloalkanes or alkyl halides are a group of chemical compounds, consisting of alkanes, such as methane or ethane, with one or more halogens linked, such as chlorine or fluorine.
Substitution reaction
In a substitution reaction, a functional group in a particular chemical compound is replaced by another group.
Nucleophilic substitution
Nucleophilic substitution is a fundamental class of substitution reaction in which an electron rich nucleophile selectively bonds with or attacks the positive charge of a group or atom called the leaving group.
Elimination reaction
An elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one or two-step mechanism.
A carbocation is an ion with a positively-charged carbon atom which are intermediates in the E1 and SN1 mechanisms involving reaction with haloalkanes.
Leaving group
A leaving group such as halide is an atom or group of atoms which may detach relatively easily from a chemical substance.
SN1 reaction
The SN1 reaction is a nucleophilic substitution reaction in organic chemistry in which the rate-determining step is unimolecular.
E1 mechanism
E1 is a model to explain a particular type of chemical elimination reaction in which there is a two-step process of elimination ionization and deprotonation.
E2 mechanism
E2 is a model to explain a particular type of chemical elimination reaction in which there is a one-step process of elimination with a single transition state.
SN2 reaction
The SN2 reaction is a type of nucleophilic substitution in which a lone pair from a nucleophile attacks an electron deficient electrophilic center and bonds to it, expelling another group from the opposite side called a leaving group.
Williamson ether synthesis
The Williamson ether synthesis involves the reaction of an alkoxide ion with a primary alkyl halide via an SN2 reaction.
Polar aprotic solvent
Polar aprotic solvents are solvents that share ion dissolving power with protic solvents but lack an acidic hydrogen. These are favorable solvents for SN2 reactions.
In chemistry racemization refers to partial conversion of one enantiomer into another, which often occurs in SN1 substitution.
Gilman reagent
Gilman reagents are lithium and copper reagent compounds which are useful because they react with chlorides, bromides, and iodides to replace the halide group with an alkyl group.
Walden inversion
Walden inversion is the inversion of configuration of a chiral centre in a molecule in a chemical reaction. It is encountered in for example a SN2 reaction.
Alkylation is the transfer of an alkyl group from one molecule to another.
Corey-House synthesis
The Corey-House synthesis is an organic reaction that involves the reaction of a lithium dialkyl cuprate with an alkyl halide to form a new alkane.
Wurtz reaction
The Wurtz reaction is a coupling reaction in organic chemistry, organometallic chemistry and recently inorganic main group polymers, whereby two alkyl halides are reacted with sodium to form a new carbon-carbon bond.

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