Haloalkanes and Haloarenes Practice Flashcards

Comprehensive practice flashcards covering vocabulary, reactions, and nomenclature for the JEE Haloalkanes and Haloarenes chapter.

Haloalkane (Alkyl halide)

A compound formed by the replacement of hydrogen atom(s) in an aliphatic hydrocarbon by halogen atom(s), where the halogen is attached to an $sp^3$ hybridised carbon atom.

Haloarene (Aryl halide)

A compound formed by the replacement of hydrogen atom(s) in an aromatic hydrocarbon by halogen atom(s), where the halogen is attached to an $sp^2$ hybridised carbon atom of an aryl group.

Geminal-dihalides

Dihalides where two halogen atoms are attached to the same carbon atom; their common name is Alkylidene halides (e.g., Ethylidene chloride).

Vicinal dihalides

Dihalides where two halogen atoms are attached to adjacent carbon atoms; their common name is Alkylene dihalides (e.g., Ethylene dibromide).

Allylic halides

Compounds in which the halogen atom is bonded to an $sp^3$-hybridised carbon atom situated next to a carbon-carbon double bond ($C=C$).

Benzylic halides

Compounds in which the halogen atom is bonded to an $sp^3$-hybridised carbon atom situated next to an aromatic ring.

Vinylic halides

Compounds in which the halogen atom is bonded to an $sp^2$-hybridised carbon atom of a carbon-carbon double bond.

Bond Enthalpy Order

The order of bond energy for methyl halides is $H_3C-F > H_3C-Cl > H_3C-Br > H_3C-I$.

Bond Length Order

The order of distance between the carbon and halogen atoms is $H_3C-F < H_3C-Cl < H_3C-Br < H_3C-I$.

Dipole Moment Exception

In the dipole moment order for methyl halides, chloromethane precedes fluoromethane: $H_3C-Cl > H_3C-F > H_3C-Br > H_3C-I$.

Lucas Reagent

A mixture of concentrated $HCl$ and anhydrous $ZnCl_2$ used to distinguish between $1^\circ, 2^\circ,$ and $3^\circ$ alcohols.

Darzen's Process

The reaction of alcohols with Thionyl Chloride ($SOCl_2$) to prepare pure alkyl halides, as the gaseous by-products ($SO_2$ and $HCl$) escape the reaction mixture.

Kharash Effect (Peroxide Effect)

The addition of $HBr$ to unsymmetrical alkenes in the presence of peroxides, resulting in the major product following Anti-M Rule (Anti-Markovnikov addition).

NBS (N-Bromo succinimide)

A reagent used specifically for substitution at allylic and benzylic positions using a free radical mechanism.

Test for Unsaturation

The decolourisation of a Bromine ($Br_2$) solution in $CCl_4$ when it reacts with an alkene or alkyne.

Finkelstein Reaction

A halogen exchange reaction where alkyl chlorides or bromides react with $NaI$ in dry acetone to form alkyl iodides ($R-I$).

Swarts Reaction

A halogen exchange reaction used to synthesize alkyl fluorides ($R-F$) using metallic fluorides such as $AgF, Hg_2F_2, SbF_3,$ or $CoF_2$.

Gattermann Reaction

The preparation of aryl halides by treating benzene diazonium salts with $HCl$ or $HBr$ in the presence of copper powder.

Sandmeyer Reaction

The preparation of aryl halides using benzene diazonium chloride and cuprous halides ($Cu_2Cl_2$ or $Cu_2Br_2$).

Hunsdiecker Reaction

The preparation of alkyl bromides by reacting silver salts of carboxylic acids ($R-COOAg$) with $Br_2$ in $CCl_4$ via free radical mechanism.

Walden Inversion

The 100% inversion of configuration that occurs during an $S_N2$ (Substitution nucleophilic Bimolecular) reaction.

Ambident Nucleophiles

Nucleophiles that possess two donor sites but use only one at a time to form a bond (e.g., $CN^-, NO_2^-, SCN^-$).

Saytzeff Rule

In elimination reactions, the most stable alkene (the more substituted one with more $\alpha$-hydrogens) is the major product.

Grignard Reagent

Organometallic compounds formed by the reaction of alkyl halides with Magnesium in dry ether, represented by the general formula $R-MgX$.

Wurtz Reaction

The coupling of two alkyl halides with Sodium in dry ether to form a symmetrical hydrocarbon ($R-R$).

Fittig Reaction

The reaction of two aryl halides with Sodium in dry ether to form Biphenyl.

Phosgene

A toxic, extremely poisonous gas ($COCl_2$) formed by the slow oxidation of chloroform ($CHCl_3$) by air in the presence of sunlight.

DDT

p,p'-Dichlorodiphenyltrichloroethane; a polyhalogen compound effectively used against mosquitoes that spread malaria.

Chloropicrin (Tear gas)

A compound with the formula $CCl_3NO_2$, synthesized by reacting Chloroform with concentrated nitric acid ($HNO_3$).

Freons

Chlorofluorocarbon compounds of methane and ethane that are extremely stable, non-toxic, noncorrosive, and used in refrigeration.