Nucleophilic Substitution in Haloalkanes · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Why nucleophiles pick on haloalkanes

Science · Chemistry · ages 16-18
Name ______________________   Date ____________

  1. What does hydroxide attack on a haloalkane produce?

    • A nitrile
    • An amine
    • An alcohol

  2. Why does the carbon in a carbon-halogen bond attract nucleophiles?

    • It carries a partial positive charge as the halogen pulls electrons away
    • It carries a full negative charge
    • Halogens push electrons onto carbon

  3. What does ammonia attack on a haloalkane produce?

    • An amine, as ammonia bonds through nitrogen
    • An alcohol
    • A nitrile with a longer chain

  4. What does cyanide attack produce, and why does it matter?

    • An alcohol, useful as a solvent
    • An amine, useful as a base
    • A nitrile, and the carbon chain grows one longer

  5. Rank chloro, bromo and iodo compounds by substitution rate, fastest first.

    • Chloro, bromo, iodo
    • Iodo, bromo, chloro
    • Bromo, chloro, iodo

  6. The most polar carbon-halogen bond always breaks fastest in substitution.

    Circle one:   True   False

  7. A student names the cyanide substitution product an amine. What is the error?

    • Cyanide bonds through carbon, giving a nitrile, not an amine
    • Cyanide cannot attack haloalkanes
    • Amines and nitriles are the same family

  8. Why does iodoethane hydrolyse faster than chloroethane even though the carbon-chlorine bond is more polar?

    • Iodide leaves more easily as the C-I bond is weaker
    • Chloroethane cannot be attacked at all
    • Polarity speeds reactions and iodine is more polar
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Why nucleophiles pick on haloalkanes W1-mt_QG-nKlnVvW-s1

  1. An alcohol · Hydroxide swaps the halogen for an OH group.
  2. It carries a partial positive charge as the halogen pulls electrons away · The pulled electrons leave carbon electron poor and inviting.
  3. An amine, as ammonia bonds through nitrogen · Nitrogen bonds to carbon and a lost proton leaves the amino group.
  4. A nitrile, and the carbon chain grows one longer · Cyanide bonds through carbon, adding one carbon to the skeleton.
  5. Iodo, bromo, chloro · Weakest bond breaks easiest, so iodo leads and chloro trails.
  6. False · Bond strength beats polarity: iodo is fastest though least polar.
  7. Cyanide bonds through carbon, giving a nitrile, not an amine · The bonding atom names the family: carbon means nitrile.
  8. Iodide leaves more easily as the C-I bond is weaker · Breaking the bond dominates, and the weaker C-I bond breaks first.
Worksheet · LightMySky