3. Acids and Bases

Complete the following acid–base reactions. In each case, indicate whether the equilibrium favors the reactants or the products, and explain your reasoning.

(f) (CH₃)₃C–O^– + H₂O ⇌

Write equations for the following acid–base reactions. Label the conjugate acids and bases, and show any inductive stabilization. Predict whether the equilibrium favors the reactants or products. Try to do this without using a table of pK_a values, but if you need a hint, you can consult Appendix 4.

g. NaOCH₂CH₃ + Cl₂CHCH₂OH

h. H₂Se + NaNH₂

i. CH₃CHFCOOH + FCH₂CH₂COO^–

For each of the following compounds (here shown in their acidic forms), write the form that ­predominates in a solution with a pH = 5.5:

c. H₃O⁺ (pK_a = −1.7)

d. HBr (pK_a = −9)

Do the equilibria of the following acid–base reactions lie to the right or the left? (The pK_a of H2O2 is 11.6.)

HOOH + HO⁻ ⇌ HOO⁻ + H2O

RC☰CH + HOO⁻ ⇌ RC☰C⁻ + HOOH

Using pK_a values for the conjugate acids of the bases on each side of the reaction arrow, identify which side of the equilibrium would be favored in the following hypothetical reactions.

(a)

For each of the following acid–base reactions, (i) predict which side of the reaction you expect to be favored. If a pK_a is not one of the ten common ones we learned in Chapter 4, it will be given to you.

(a)

An acid has a K_a of 4.53 × 10⁻⁶ in water. What is its K_eq for reaction with water in a dilute solution? ([H₂O] = 55.5 M)

For each of the following reactions, suggest which solvent(s) would be compatible with the acids and bases involved. (We will ignore any other possible reactions for now.) Your choices of solvents are pentane, diethyl ether, ethanol, water, and ammonia. Refer to Appendix 4 for any needed values of pK_a, or estimate them. 

c.

d.

For each of the following compounds, indicate the pH at which

b. more than 99% of the compound is in a form that possesses a charge.

    1. CH₃CH₂COOH (pK_a = 4.9)

    2. CH₃N⁺H₃ (pK_a = 10.7)