Amines and Amides: Basicity and the Nitrogen Functional Groups · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

The lone pair runs the show

Science · Chemistry · ages 17-18
Name ______________________   Date ____________

  1. Why is aniline a much weaker base than methylamine?

    • It has no nitrogen atom at all
    • Its lone pair is pulled into the benzene ring
    • It cannot dissolve in any solvent

  2. What makes an amine act as a base?

    • Its nitrogen lone pair can grab a proton
    • Its carbon chains dissolve in water
    • Its smell neutralizes acids

  3. Amides are strong bases, just like amines.

    Circle one:   True   False

  4. An amine reacts with an acyl chloride. What is lost, and what forms?

    • Water is lost and a nitrile forms
    • Ammonia is lost and a haloalkane forms
    • HCl is lost and an amide forms

  5. A haloalkane reacts with ammonia, yet the pot ends up holding secondary and tertiary amines too. Why?

    • Ammonia adds three carbons in one step
    • The amine product attacks more haloalkane and reacts further
    • Nitriles wander into the mixture on their own

  6. An amine has its nitrogen bonded to two carbon groups. Which class is it?

    • Secondary amine
    • Primary amine
    • Amide

  7. Rank these by base strength, strongest first: aniline, ammonia, ethylamine.

    • Aniline, ammonia, ethylamine
    • Ethylamine, ammonia, aniline
    • Ammonia, ethylamine, aniline

  8. A student claims the amide C-N bond snaps as easily as an ordinary single bond. What is wrong?

    • Amides contain no carbon-nitrogen bond
    • Single bonds are always stronger than double bonds
    • Resonance gives it partial double character, so it is rigid and strong
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Answer key

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

The lone pair runs the show W1-mt_cGP3ZJ8S6h-s1

  1. Its lone pair is pulled into the benzene ring · Resonance with the ring leaves the pair far less available.
  2. Its nitrogen lone pair can grab a proton · The free lone pair accepts a proton, which is exactly basic behavior.
  3. False · The amide lone pair is shared with the carbonyl, so amides are not basic.
  4. HCl is lost and an amide forms · Nitrogen attacks the carbonyl carbon, chloride leaves, and HCl is lost.
  5. The amine product attacks more haloalkane and reacts further · Each amine product stays nucleophilic, so it keeps alkylating further.
  6. Secondary amine · Two carbon swaps on ammonia defines a secondary amine.
  7. Ethylamine, ammonia, aniline · Alkyl donation lifts ethylamine above ammonia, while the ring sinks aniline last.
  8. Resonance gives it partial double character, so it is rigid and strong · The shared pair stiffens the link, which is why proteins rely on it.
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