Acid Base Equilibrium Practice Problems

Propose suitable products for the following acid-base reactions:

Also, predict the direction of equilibrium for each reaction.

Which of the given solvents will be compatible with the acids and bases involved in the following reactions (Ignoring any side reactions)?

Solvent choices = diethyl ether, ethanol, and water.

a. CH₃CH₂Li + CH₃—C≡C—H → CH₃—CH₃ + CH₃—C≡CLi 

b. CH₃CH₂Li + (CH₃)₂CH—OH → CH₃—CH₃ + (CH₃)₂CH—OLi 

The acid-catalyzed hydrolysis of 6-cyclopentylhexyl 4-phenylbutanoate yields 4-phenylbutanoic acid and 6-cyclopentylhexanol. Complete the simplified flow chart for separating the carboxylic acid from the alcohol product by identifying X1 to X6.

Using the given K_eq value, identify the weakest acid and the weakest base in the reaction given below.

Using the given equilibrium constant, identify the weakest acid and the weakest base in the reaction given below.

Using the given equilibrium constant value, identify the weakest acid and the weakest base in the following reaction.

Using the given equilibrium constant value, identify the strongest acid and the strongest base in the given reaction.

Using the given equilibrium constant value, identify the strongest acid and the strongest base in the following reaction.

Using the given equilibrium constant values, identify the strongest acid and the strongest base in the reaction shown below.

Use the K_eq values mentioned with each of the following equations to determine how much stronger acid is phenol than acetamide.

Use the K_eq values stated in each of the following equations to determine the factor by which cyanomethanide is a stronger base than pyrrolide.

Does ethanol behave as an acid or a base in the following chemical reaction?
(pKa of ethanol and ethylamine are 15 and 40 respectively)
CH₃CH₂OH + CH₃CH₂NH₂  →

Which of the bases given below are able to deprotonate propanoic acid (pK_a = 4.88) in an acid-base reaction that favors the formation of products?
(i) CH₃O⁻ (pK_a of CH₃OH = 15.9)
(ii) NH₃ (pK_a of NH₄⁺ = 9.4)
(iii) CH₃C≡C⁻ (pK_a of CH₃C≡CH = 25)
(iv) CH₃CH₂OH (pK_a of CH₃CH₂OH₂⁺ = −2.5)
(v) H₂O (pK_a of H₃O⁺ = −1.7)
(vi) Br⁻ (pK_a of HBr = −9)

For CH₃CH₂CH₂NH₃⁺ (pKa = 10.7), draw the form that predominates at:
(i) pH = 3.5
(ii) pH = 6.8
(iii) pH = 9.5
(iv) pH = 13.5

Create a scheme to separate the following compounds from a mixture. 1.0 M HBr, 1.0 M KOH, water and diethyl ether are available for you to use.

The pK_a values of the carboxylic acid and the protonated amine groups of valine are shown below.

Write the structure of valine in a solution with a pH of 7.4 (physiological pH).

An acid-base equilibrium favors the formation of the weaker acid. Which of the following reactions favor the formation of products?

Give the products of the acid-base reaction shown below. Use the p K_a values to determine whether the reaction favors the product or reactant side at equilibrium. (pK_a of the acid on the reactant side is  4.87, p K_a of the acid on the product side is 16.0)

Draw the products of the acid-base reaction shown below and use the p K_a values to indicate whether equilibrium favors the reactants or the products. (pK_a of the acid on the reactant side is 16.5, p K_a of the acid on product side is 36.0)

Which of the compounds given below can be deprotonated by CH₃O⁻ in an acid-base reaction that favors product formation? (pK_a of CH₃OH = 15.9)
(i) HCOOH (pK_a = 3.7)
(ii) CH₃NH₂ (pK_a = 40)
(iii) NH₄⁺ (pK_a = 9.4)
(iv) HC≡CH (pK_a = 25)

Write the form that predominates when each of the following compounds is added to a solution with a pH = 6.5:
(i) CH₂BrCOOH (pKa = 2.86)
(ii) NH₄⁺ (pKa = 9.40)

(i) Determine the pH at which the concentration of the acidic form of a compound is 20 times greater than its basic form (pKa = 8.8).
(ii) Determine the pH at which 60% of a compound is in its basic form (pKa = 8.0)

For each pair of reactions, determine which reaction favors the formation of products the most.

Reaction A: HCOOH + NH₃ ⇌ HCOO^— + NH₄⁺

Reaction B: CH₃COOH + NH₃ ⇌ CH₃COO^— + NH₄⁺

If propanoic acid (pK_a = 4.9) is in an acidic aqueous solution with a pH of 5.2, determine the percentage of propanoic acid existing in its acidic form.

For (CH₃)₂NH₂⁺ (pK_a = 10.7), write the form that predominates in a solution with a pH of 8.2.

Ethoxide cannot be used to deprotonate cyclohexane in a reaction that favors the formation of a carbanion. Explain why this is true.

An acid-base equilibrium favors the formation of the weaker acid. Which of the following reactions favor the formation of products?

Complete the following acid-base reactions and predict the equilibrium positions of these reactions using the information given in the table.

a. CH₃OH + NaNH₂
b. ⁻CN + CH₃COOH
c. CH₃CH₂OH + HCOO⁻

Using the pK_a values of acetic acid and benzoic acid, predict whether the equilibrium will favor the products or the reactants in the following reaction.

Phenols are less acidic than carboxylic acids and can only be deprotonated using a strong base. Explain how acid-base extraction can be used to isolate the pure compounds from the mixture of acetophenone (acetylbenzene), 2-methylphenol, and o-toluic acid (2-methylbenzoic acid).

How can acid-base extraction be utilized to separate the mixture of given compounds?

Benzylamine, m-cresol (3-methylphenol), p-toluic acid, and 2-phenylethanol.

For each of the following Brønsted–Lowry acid–base reactions (i): 3-methylpyridine + 4-chlorophenol and (ii): 3-methylpyridine + 4-chlorobenzoic acid, write the products of a transfer of the most acidic proton on the acid to the most basic site on the base. Also, determine whether the reactants side or the products side is favored in each of the acid-base reactions by using the pK_b values for the bases and the pK_a values for the acids.

Some equations of acid-base reactions are given below. Write the products in each case if any significant reaction is possible.

a. CH₃—C≡C—H + NaOH
b. CH₃—C≡C—H + CH₃Li
c. CH₃—C≡C—H + NaNH₂

Consider the following acid-base reaction.

Write the products, identify the direction that is favored by the equilibrium, and give an explanation for your answer.

Consider the following acid-base reaction.

Write the products, identify the direction that is favored by the equilibrium, and give an explanation for your answer.