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Haloalkanes and Haloarenes Cheat Sheet 
(EduRev) 
Introduction and Classification 
Key Concepts 
? Haloalkanes: R–X (X = F, Cl, Br, I), classified as 1°, 2°, 3° based on carbon substitution. 
? Haloarenes: Ar–X, halogen on aromatic ring. 
? Nomenclature: IUPAC, e.g., CH
3
CH
2
Br ? 1-bromoethane, C
6
H
5
Cl ? chlorobenzene. 
Physical Properties 
Key Concepts 
? Boiling Points: Increase with molecular weight (I > Br > Cl > F). 
? Solubility: Insoluble in water, soluble in organic solvents. 
? Dipole Moment: Haloalkanes > haloarenes due to resonance in Ar–X. 
Preparation Methods 
Haloalkanes 
? From alcohols: R–OH + HX ? R–X + H
2
O (ZnCl
2
, 1°/2°). 
? From alkenes: R–CH=CH
2
 + HX ? R–CHX–CH
3
 (Markovnikov). 
? Halogen exchange: R–Br + NaI ? R–I + NaBr (Finkelstein, acetone). 
Page 2


Haloalkanes and Haloarenes Cheat Sheet 
(EduRev) 
Introduction and Classification 
Key Concepts 
? Haloalkanes: R–X (X = F, Cl, Br, I), classified as 1°, 2°, 3° based on carbon substitution. 
? Haloarenes: Ar–X, halogen on aromatic ring. 
? Nomenclature: IUPAC, e.g., CH
3
CH
2
Br ? 1-bromoethane, C
6
H
5
Cl ? chlorobenzene. 
Physical Properties 
Key Concepts 
? Boiling Points: Increase with molecular weight (I > Br > Cl > F). 
? Solubility: Insoluble in water, soluble in organic solvents. 
? Dipole Moment: Haloalkanes > haloarenes due to resonance in Ar–X. 
Preparation Methods 
Haloalkanes 
? From alcohols: R–OH + HX ? R–X + H
2
O (ZnCl
2
, 1°/2°). 
? From alkenes: R–CH=CH
2
 + HX ? R–CHX–CH
3
 (Markovnikov). 
? Halogen exchange: R–Br + NaI ? R–I + NaBr (Finkelstein, acetone). 
Haloarenes 
? Electrophilic substitution: C
6
H
6
 + Cl
2
 ? C
6
H
5
Cl (FeCl
3
). 
? Sandmeyer’s: Ar–N
2
+
Cl
-
 + CuCl ? Ar–Cl + N
2
. 
Chemical Reactions of Haloalkanes 
Nucleophilic Substitution 
? S
N
2: 1°, concerted, inversion, e.g., CH
3
Br + OH
-
 ? CH
3
OH + Br
-
. 
? S
N
1: 3°, carbocation, racemization, e.g., (CH
3
)
3
CBr ? (CH
3
)
3
C
+
 ? (CH
3
)
3
COH. 
Elimination 
? E2: 2°/3°, concerted, Zaitsev’s rule, e.g., CH
3
CHBrCH
3
 + OH
-
 ? CH
3
CH=CH
2
. 
? E1: 3°, carbocation, e.g., (CH
3
)
3
CBr ? (CH
3
)
2
C=CH
2
. 
Reactions with Metals 
? Grignard: R–X + Mg ? R–MgX (dry ether). 
? Wurtz: 2R–X + 2Na ? R–R + 2NaX. 
Chemical Reactions of Haloarenes 
Key Reactions 
? Electrophilic Substitution: Halogens o,p-directing, deactivating, e.g., C
6
H
5
Cl + HNO
3
 ? 
o/p-C
6
H
4
ClNO
2
. 
? Nucleophilic Substitution: Dow’s process, C
6
H
5
Cl + NaOH ? C
6
H
5
OH (350°C, 300 
atm). 
? Benzyne Mechanism: C
6
H
5
Cl + NH
2
-
 ? C
6
H
5
NH
2
. 
Page 3


Haloalkanes and Haloarenes Cheat Sheet 
(EduRev) 
Introduction and Classification 
Key Concepts 
? Haloalkanes: R–X (X = F, Cl, Br, I), classified as 1°, 2°, 3° based on carbon substitution. 
? Haloarenes: Ar–X, halogen on aromatic ring. 
? Nomenclature: IUPAC, e.g., CH
3
CH
2
Br ? 1-bromoethane, C
6
H
5
Cl ? chlorobenzene. 
Physical Properties 
Key Concepts 
? Boiling Points: Increase with molecular weight (I > Br > Cl > F). 
? Solubility: Insoluble in water, soluble in organic solvents. 
? Dipole Moment: Haloalkanes > haloarenes due to resonance in Ar–X. 
Preparation Methods 
Haloalkanes 
? From alcohols: R–OH + HX ? R–X + H
2
O (ZnCl
2
, 1°/2°). 
? From alkenes: R–CH=CH
2
 + HX ? R–CHX–CH
3
 (Markovnikov). 
? Halogen exchange: R–Br + NaI ? R–I + NaBr (Finkelstein, acetone). 
Haloarenes 
? Electrophilic substitution: C
6
H
6
 + Cl
2
 ? C
6
H
5
Cl (FeCl
3
). 
? Sandmeyer’s: Ar–N
2
+
Cl
-
 + CuCl ? Ar–Cl + N
2
. 
Chemical Reactions of Haloalkanes 
Nucleophilic Substitution 
? S
N
2: 1°, concerted, inversion, e.g., CH
3
Br + OH
-
 ? CH
3
OH + Br
-
. 
? S
N
1: 3°, carbocation, racemization, e.g., (CH
3
)
3
CBr ? (CH
3
)
3
C
+
 ? (CH
3
)
3
COH. 
Elimination 
? E2: 2°/3°, concerted, Zaitsev’s rule, e.g., CH
3
CHBrCH
3
 + OH
-
 ? CH
3
CH=CH
2
. 
? E1: 3°, carbocation, e.g., (CH
3
)
3
CBr ? (CH
3
)
2
C=CH
2
. 
Reactions with Metals 
? Grignard: R–X + Mg ? R–MgX (dry ether). 
? Wurtz: 2R–X + 2Na ? R–R + 2NaX. 
Chemical Reactions of Haloarenes 
Key Reactions 
? Electrophilic Substitution: Halogens o,p-directing, deactivating, e.g., C
6
H
5
Cl + HNO
3
 ? 
o/p-C
6
H
4
ClNO
2
. 
? Nucleophilic Substitution: Dow’s process, C
6
H
5
Cl + NaOH ? C
6
H
5
OH (350°C, 300 
atm). 
? Benzyne Mechanism: C
6
H
5
Cl + NH
2
-
 ? C
6
H
5
NH
2
. 
? Wurtz-Fittig: Ar–X + R–X + 2Na ? Ar–R. 
Reaction Mechanisms 
Haloalkanes 
? S
N
2: Nucleophile attacks C, X leaves, transition state, inversion. 
? S
N
1: X leaves, forms carbocation, nucleophile attacks, racemization. 
? E2: Base abstracts ß-H, X leaves, alkene forms, anti-elimination. 
? E1: X leaves, carbocation forms, base abstracts ß-H. 
Haloarenes 
? Benzyne: Base abstracts H, X leaves, forms benzyne, nucleophile adds. 
? Electrophilic Substitution: Electrophile attacks ring, H leaves, forms substituted 
product. 
Applications and Environmental Impact 
Key Concepts 
? Uses: Solvents (CHCl
3
, CCl
4
), refrigerants (CFCs), pesticides (DDT). 
? Environmental: CFCs deplete ozone, DDT is toxic and persistent. 
Stereochemistry 
Key Concepts 
? Chirality: Haloalkanes with chiral carbon (e.g., CH
3
CHBrCH
2
CH
3
) are optically active. 
? S
N
2: Inversion of configuration. 
Page 4


Haloalkanes and Haloarenes Cheat Sheet 
(EduRev) 
Introduction and Classification 
Key Concepts 
? Haloalkanes: R–X (X = F, Cl, Br, I), classified as 1°, 2°, 3° based on carbon substitution. 
? Haloarenes: Ar–X, halogen on aromatic ring. 
? Nomenclature: IUPAC, e.g., CH
3
CH
2
Br ? 1-bromoethane, C
6
H
5
Cl ? chlorobenzene. 
Physical Properties 
Key Concepts 
? Boiling Points: Increase with molecular weight (I > Br > Cl > F). 
? Solubility: Insoluble in water, soluble in organic solvents. 
? Dipole Moment: Haloalkanes > haloarenes due to resonance in Ar–X. 
Preparation Methods 
Haloalkanes 
? From alcohols: R–OH + HX ? R–X + H
2
O (ZnCl
2
, 1°/2°). 
? From alkenes: R–CH=CH
2
 + HX ? R–CHX–CH
3
 (Markovnikov). 
? Halogen exchange: R–Br + NaI ? R–I + NaBr (Finkelstein, acetone). 
Haloarenes 
? Electrophilic substitution: C
6
H
6
 + Cl
2
 ? C
6
H
5
Cl (FeCl
3
). 
? Sandmeyer’s: Ar–N
2
+
Cl
-
 + CuCl ? Ar–Cl + N
2
. 
Chemical Reactions of Haloalkanes 
Nucleophilic Substitution 
? S
N
2: 1°, concerted, inversion, e.g., CH
3
Br + OH
-
 ? CH
3
OH + Br
-
. 
? S
N
1: 3°, carbocation, racemization, e.g., (CH
3
)
3
CBr ? (CH
3
)
3
C
+
 ? (CH
3
)
3
COH. 
Elimination 
? E2: 2°/3°, concerted, Zaitsev’s rule, e.g., CH
3
CHBrCH
3
 + OH
-
 ? CH
3
CH=CH
2
. 
? E1: 3°, carbocation, e.g., (CH
3
)
3
CBr ? (CH
3
)
2
C=CH
2
. 
Reactions with Metals 
? Grignard: R–X + Mg ? R–MgX (dry ether). 
? Wurtz: 2R–X + 2Na ? R–R + 2NaX. 
Chemical Reactions of Haloarenes 
Key Reactions 
? Electrophilic Substitution: Halogens o,p-directing, deactivating, e.g., C
6
H
5
Cl + HNO
3
 ? 
o/p-C
6
H
4
ClNO
2
. 
? Nucleophilic Substitution: Dow’s process, C
6
H
5
Cl + NaOH ? C
6
H
5
OH (350°C, 300 
atm). 
? Benzyne Mechanism: C
6
H
5
Cl + NH
2
-
 ? C
6
H
5
NH
2
. 
? Wurtz-Fittig: Ar–X + R–X + 2Na ? Ar–R. 
Reaction Mechanisms 
Haloalkanes 
? S
N
2: Nucleophile attacks C, X leaves, transition state, inversion. 
? S
N
1: X leaves, forms carbocation, nucleophile attacks, racemization. 
? E2: Base abstracts ß-H, X leaves, alkene forms, anti-elimination. 
? E1: X leaves, carbocation forms, base abstracts ß-H. 
Haloarenes 
? Benzyne: Base abstracts H, X leaves, forms benzyne, nucleophile adds. 
? Electrophilic Substitution: Electrophile attacks ring, H leaves, forms substituted 
product. 
Applications and Environmental Impact 
Key Concepts 
? Uses: Solvents (CHCl
3
, CCl
4
), refrigerants (CFCs), pesticides (DDT). 
? Environmental: CFCs deplete ozone, DDT is toxic and persistent. 
Stereochemistry 
Key Concepts 
? Chirality: Haloalkanes with chiral carbon (e.g., CH
3
CHBrCH
2
CH
3
) are optically active. 
? S
N
2: Inversion of configuration. 
? S
N
1: Racemization due to planar carbocation. 
Problem-Solving Tactics 
? Identify substrate type (1°, 2°, 3°, alkyl vs. aryl) to predict S
N
1/S
N
2 or E1/E2. 
? Check nucleophile strength and solvent (polar protic ? S
N
1/E1, polar aprotic ? S
N
2/E2). 
? Use Zaitsev’s rule for elimination products. 
? Consider resonance in haloarenes for low reactivity. 
? Check chirality for stereochemical outcomes. 
Reaction Table 
Reaction Type Reactants Reagents/Conditio
ns 
Products 
Haloalkane Prep R–OH HX, ZnCl
2 
R–X + H
2
O 
Haloalkane Prep R–CH=CH
2 
HX R–CHX–CH
3 
Finkelstein R–Br NaI, acetone R–I + NaBr 
Haloarene Prep C
6
H
6 
Cl
2
, FeCl
3 
C
6
H
5
Cl 
Page 5


Haloalkanes and Haloarenes Cheat Sheet 
(EduRev) 
Introduction and Classification 
Key Concepts 
? Haloalkanes: R–X (X = F, Cl, Br, I), classified as 1°, 2°, 3° based on carbon substitution. 
? Haloarenes: Ar–X, halogen on aromatic ring. 
? Nomenclature: IUPAC, e.g., CH
3
CH
2
Br ? 1-bromoethane, C
6
H
5
Cl ? chlorobenzene. 
Physical Properties 
Key Concepts 
? Boiling Points: Increase with molecular weight (I > Br > Cl > F). 
? Solubility: Insoluble in water, soluble in organic solvents. 
? Dipole Moment: Haloalkanes > haloarenes due to resonance in Ar–X. 
Preparation Methods 
Haloalkanes 
? From alcohols: R–OH + HX ? R–X + H
2
O (ZnCl
2
, 1°/2°). 
? From alkenes: R–CH=CH
2
 + HX ? R–CHX–CH
3
 (Markovnikov). 
? Halogen exchange: R–Br + NaI ? R–I + NaBr (Finkelstein, acetone). 
Haloarenes 
? Electrophilic substitution: C
6
H
6
 + Cl
2
 ? C
6
H
5
Cl (FeCl
3
). 
? Sandmeyer’s: Ar–N
2
+
Cl
-
 + CuCl ? Ar–Cl + N
2
. 
Chemical Reactions of Haloalkanes 
Nucleophilic Substitution 
? S
N
2: 1°, concerted, inversion, e.g., CH
3
Br + OH
-
 ? CH
3
OH + Br
-
. 
? S
N
1: 3°, carbocation, racemization, e.g., (CH
3
)
3
CBr ? (CH
3
)
3
C
+
 ? (CH
3
)
3
COH. 
Elimination 
? E2: 2°/3°, concerted, Zaitsev’s rule, e.g., CH
3
CHBrCH
3
 + OH
-
 ? CH
3
CH=CH
2
. 
? E1: 3°, carbocation, e.g., (CH
3
)
3
CBr ? (CH
3
)
2
C=CH
2
. 
Reactions with Metals 
? Grignard: R–X + Mg ? R–MgX (dry ether). 
? Wurtz: 2R–X + 2Na ? R–R + 2NaX. 
Chemical Reactions of Haloarenes 
Key Reactions 
? Electrophilic Substitution: Halogens o,p-directing, deactivating, e.g., C
6
H
5
Cl + HNO
3
 ? 
o/p-C
6
H
4
ClNO
2
. 
? Nucleophilic Substitution: Dow’s process, C
6
H
5
Cl + NaOH ? C
6
H
5
OH (350°C, 300 
atm). 
? Benzyne Mechanism: C
6
H
5
Cl + NH
2
-
 ? C
6
H
5
NH
2
. 
? Wurtz-Fittig: Ar–X + R–X + 2Na ? Ar–R. 
Reaction Mechanisms 
Haloalkanes 
? S
N
2: Nucleophile attacks C, X leaves, transition state, inversion. 
? S
N
1: X leaves, forms carbocation, nucleophile attacks, racemization. 
? E2: Base abstracts ß-H, X leaves, alkene forms, anti-elimination. 
? E1: X leaves, carbocation forms, base abstracts ß-H. 
Haloarenes 
? Benzyne: Base abstracts H, X leaves, forms benzyne, nucleophile adds. 
? Electrophilic Substitution: Electrophile attacks ring, H leaves, forms substituted 
product. 
Applications and Environmental Impact 
Key Concepts 
? Uses: Solvents (CHCl
3
, CCl
4
), refrigerants (CFCs), pesticides (DDT). 
? Environmental: CFCs deplete ozone, DDT is toxic and persistent. 
Stereochemistry 
Key Concepts 
? Chirality: Haloalkanes with chiral carbon (e.g., CH
3
CHBrCH
2
CH
3
) are optically active. 
? S
N
2: Inversion of configuration. 
? S
N
1: Racemization due to planar carbocation. 
Problem-Solving Tactics 
? Identify substrate type (1°, 2°, 3°, alkyl vs. aryl) to predict S
N
1/S
N
2 or E1/E2. 
? Check nucleophile strength and solvent (polar protic ? S
N
1/E1, polar aprotic ? S
N
2/E2). 
? Use Zaitsev’s rule for elimination products. 
? Consider resonance in haloarenes for low reactivity. 
? Check chirality for stereochemical outcomes. 
Reaction Table 
Reaction Type Reactants Reagents/Conditio
ns 
Products 
Haloalkane Prep R–OH HX, ZnCl
2 
R–X + H
2
O 
Haloalkane Prep R–CH=CH
2 
HX R–CHX–CH
3 
Finkelstein R–Br NaI, acetone R–I + NaBr 
Haloarene Prep C
6
H
6 
Cl
2
, FeCl
3 
C
6
H
5
Cl 
Reaction Type Reactants Reagents/Conditio
ns 
Products 
Sandmeyer’s Ar–N
2
+
Cl
- 
CuCl Ar–Cl + N
2 
S
N
2 CH
3
Br OH
-
, polar aprotic CH
3
OH + Br
- 
S
N
1 (CH
3
)
3
CBr H
2
O, polar protic (CH
3
)
3
COH 
E2 CH
3
CHBrCH
3 
OH
-
, heat CH
3
CH=CH
2 
E1 (CH
3
)
3
CBr H
2
O, heat (CH
3
)
2
C=CH
2 
Grignard R–X Mg, dry ether R–MgX 
Wurtz 2R–X 2Na R–R + 2NaX 
Electrophilic Sub C
6
H
5
Cl HNO
3
, H
2
SO
4 
C
6
H
4
ClNO
2 
Dow’s Process C
6
H
5
Cl NaOH, 350°C, 300 
atm 
C
6
H
5
OH 
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FAQs on Cheat Sheet: Haloalkanes and Haloarenes - Chemistry for JEE Main & Advanced

1. What are haloalkanes and haloarenes, and how do they differ from each other?
Ans.Haloalkanes are organic compounds in which one or more hydrogen atoms are replaced by halogen atoms (fluorine, chlorine, bromine, or iodine) in an alkane structure. Haloarenes, on the other hand, are compounds where halogen atoms are substituted in an aromatic ring. The primary difference lies in the structure: haloalkanes are aliphatic, while haloarenes are aromatic, which affects their chemical properties and reactivity.
2. What are the common methods for preparing haloalkanes?
Ans.Haloalkanes can be prepared through several methods, including: 1. Free radical halogenation of alkanes (reaction with halogens in the presence of heat or light). 2. Nucleophilic substitution reactions where alcohols react with hydrogen halides. 3. Addition reactions of halogens to alkenes or alkynes. These methods highlight the versatility in synthesizing haloalkanes from different organic compounds.
3. What are the major reactions of haloalkanes?
Ans.Haloalkanes undergo various reactions, the most significant being: 1. Nucleophilic substitution reactions (SN1 and SN2 mechanisms) where nucleophiles replace the halogen. 2. Elimination reactions where haloalkanes can form alkenes by losing a halogen and a hydrogen atom. 3. Reduction reactions that convert haloalkanes to alkanes. These reactions are crucial for understanding their reactivity in organic synthesis.
4. How are haloarenes typically synthesized?
Ans.Haloarenes are commonly synthesized through: 1. Electrophilic aromatic substitution, where halogens are introduced into the aromatic ring using electrophiles. 2. The reaction of aryl halides with metals in the presence of halogen sources. 3. The use of diazonium salts, which can be converted into haloarenes through Sandmeyer reactions. These methods reflect the unique reactivity of aromatic systems compared to aliphatic compounds.
5. What are the environmental and health impacts of haloalkanes and haloarenes?
Ans.Haloalkanes and haloarenes can have significant environmental and health impacts. Many haloalkanes are known to be toxic and can cause damage to the liver, kidneys, and nervous system upon exposure. Haloarenes, particularly polychlorinated biphenyls (PCBs), are persistent in the environment and can bioaccumulate, leading to long-term ecological harm. Their use has been restricted in many countries due to these health risks and environmental concerns.
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