Playbook
Halogen Derivatives of Alkanes
79 q - 1.83/paper - 3% HARD. Exchange and coupling reactions by name, SN1 against SN2, and a polyhalogen table.
- Questions in the bank
- 79
- q/paper (2024–25 papers)
- 1.83
- Tagged HARD
- 3%
- Subtopics
- 5
Strand: Reactions
When you’ll see it
An alkyl or aryl halide to name, prepare, substitute or eliminate — or a named polyhalogen compound.
How this chapter is tested
79 q at 1.83 a paper, 3% HARD. Classification and naming (27 q) is the largest page. Preparation (15 q) is named exchange and coupling: Finkelstein (NaI/acetone → iodide), Swarts (AgF → fluoride), Wurtz (2RX + Na → R–R) and Fittig for aryl halides.
Substitution and elimination (26 q): SN2 for primary halides (inversion, one step), SN1 for tertiary (carbocation, racemisation), and Saytzeff's rule — the more substituted alkene. Polyhalogen compounds (11 q) are a table: Freon-12, DDT and BHC, chloroform to phosgene, the war gases.
The sub-skills
The distinct skills inside the chapter, in the order to learn them.
Exchange and coupling
Finkelstein, Swarts, Wurtz, Fittig, Wurtz–Fittig — know which halide and which product.
SN1 against SN2
3° → SN1 (carbocation, racemic); 1° → SN2 (inversion).
Elimination
alc. KOH gives the alkene; Saytzeff: the more substituted alkene is major.
Polyhalogen compounds
Freon-12 CCl₂F₂; DDT and its replacement BHC; CHCl₃ oxidises to phosgene COCl₂.
Traps to expect
Distractor shapes this chapter reuses. The Traps page covers the patterns that cut across chapters.
Aqueous against alcoholic KOH
Aqueous KOH substitutes (alcohol); alcoholic KOH eliminates (alkene). The two products are both options.
Finkelstein against Swarts
Finkelstein makes iodides (NaI); Swarts makes fluorides (AgF, Hg₂F₂).
Learn it before you drill it
This chapter has full teaching notes — foundations, worked examples, self-checks and a per-subtopic mastery checkpoint. Read the notes once, then drill subtopic by subtopic below.
Halogen Derivatives of Alkanes notesDrill every halogen derivatives of alkanes question
79 questions from the bank, scoped to 5 bundled subtopics.
Drill one subtopic at a time
The 5 subtopics this playbook covers, in catalog order.
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