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Halogen Derivatives: Haloalkanes & Haloarenes formula sheet

Every formula in the Halogen Derivatives: Haloalkanes & Haloarenes chapter for JEE Main, with one line on when it applies. Topic 1 is open to everyone; sign in free to read all 20 and download the PDF.

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Classification, the C–X bond and physical properties

Types of halides
4× asked, last 2026
sp3 C–X: alkyl (1∘,2∘,3∘), allylic, benzylicsp2 C–X: vinylic CHX2=CHX, aryl CX6HX5X\begin{aligned}&sp^3\text{ C–X: alkyl }(1^\circ,2^\circ,3^\circ),\ \text{allylic},\ \text{benzylic}\\&sp^2\text{ C–X: vinylic }\ce{CH2=CHX},\ \text{aryl }\ce{C6H5X}\end{aligned}
Degree = C atoms on the C bearing X. Allylic CHX2=CH−CHX2X\ce{CH2=CH-CH2X}: X on the sp³ C next to C=C (not vinylic).
C–X bond
1× asked, last 2020
CHX3FCHX3ClCHX3BrCHX3Ilength (pm)139178193214enthalpy (kJ mol−1)452351293234\begin{array}{lcccc}&\ce{CH3F}&\ce{CH3Cl}&\ce{CH3Br}&\ce{CH3I}\\ \text{length (pm)}&139&178&193&214\\ \text{enthalpy (kJ mol}^{-1})&452&351&293&234\end{array}
R–I reacts fastest, R–F hardly. Dipole: CHX3Cl>CHX3F>CHX3Br>CHX3I\ce{CH3Cl}>\ce{CH3F}>\ce{CH3Br}>\ce{CH3I}.
Aryl and vinyl C–X
6× asked, last 2026
C–Cl: 169 pm in CX6HX5Cl vs 178 pm in CHX3Cl\text{C–Cl: }169\ \text{pm in }\ce{C6H5Cl}\ \text{vs }178\ \text{pm in }\ce{CH3Cl}
Lone pair conjugates (partial C=Cl), C is sp²: shorter, stronger. No SN1S_N1, no AgX with AgNOX3\ce{AgNO3}.
Physical properties
1× asked, last 2026
b.p.: RI>RBr>RCl>RF;longer chain, higherdichlorobenzenes: m.p. p 323>o 256 Kdichlorobenzenes: b.p. o 453>p 448 K\begin{aligned}&\text{b.p.: }\ce{RI}>\ce{RBr}>\ce{RCl}>\ce{RF};\quad \text{longer chain, higher}\\&\text{dichlorobenzenes: m.p. }p\ 323>o\ 256\ \text{K}\\&\phantom{\text{dichlorobenzenes: }}\text{b.p. }o\ 453>p\ 448\ \text{K}\end{aligned}
Branching lowers b.p. Para packs best (high m.p.); polar ortho boils higher.

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16 more formulas in 5 topics

Preparation, Nucleophilic substitution, Elimination and reactions with metals, Haloarenes: reactions and Polyhalogen compounds. Read the first part free. Sign in free with Google to read the rest and download the PDF.

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Preparation

  • From alcohols2×
  • From alkenes4×
  • Finkelstein and Swarts2×
  • Preparing haloarenes4×

Nucleophilic substitution

  • Nucleophiles and products5×
  • SN25×
  • SN15×
  • SN1 reactivity12×
  • Leaving group and nucleophile5×
  • Stereochemistry6×

Elimination and reactions with metals

  • β-Elimination8×
  • Substitution vs elimination3×
  • Grignard and Wurtz4×

Haloarenes: reactions

  • Nucleophilic substitution (Dow)4×
  • Electrophilic substitution

Polyhalogen compounds

  • Polyhalogen compounds2×

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