3. Acids and Bases

Which anion in each pair would you expect to react more quickly with H⁺?

(b)

If reacted with a strong base, which of the labeled protons would you expect to be removed first?

Which is the most acidic compound in each pair?

(a)

Rank the indicated hydrogen in the following compounds from most acidic to least acidic:

Which member of each pair is the stronger base?

c. phenolate ion or ethoxide ion

d. phenolate ion or acetate ion

Which member of each pair is the stronger base?

a. ethylamine or aniline

b. ethylamine or ethoxide ion

Which acid in each of the following pairs is stronger?

e.

f.

Purine is a heterocyclic compound with four nitrogen atoms.

a. Which nitrogen is most apt to be protonated?

b. Which nitrogen is least apt to be protonated?

Which acid in each of the following pairs is stronger?

c.

d.

For each of the following substituents, indicate whether it withdraws electrons inductively, donates electrons by hyperconjugation, withdraws electrons by resonance, or donates electrons by resonance.

d. NHCH₃

e. OCH₃

f. ⁺N(CH₃)₃

For each of the following substituents, indicate whether it withdraws electrons inductively, donates electrons by hyperconjugation, withdraws electrons by resonance, or donates electrons by resonance.

a. Br

b. CH₂CH₃

c.

Which loses a proton more readily: a methyl group bonded to cyclohexane or a methyl group bonded to benzene?

A nitro group (–NO₂) effectively stabilizes a negative charge on an adjacent carbon atom through resonance:

Two of the following nitrophenols are much more acidic than phenol itself. The third compound is only slightly more acidic than phenol. Use resonance structures of the appropriate phenoxide ions to show why two of these anions should be unusually stable.

In each pair, choose the most basic compound. Justify your answer.

(d)

In each pair, choose the most acidic compound. Justify your answer. The most acidic proton in each compound has been indicated.

(b)