3. Acids and Bases

Given the following K_eq values, how much stronger of an acid is methanol (CH₃OH) than acetylene (HC≡CH)?

Given the following K_eq values, how much stronger of a base is acetate (CH₃CO₂^-) than chloride (Cl⁻)?

Explain why an amide ion cannot be used to form a carbanion from an alkane in a reaction that favors products.

Predict the products of the following acid–base reactions, or indicate if no significant reaction would take place.

a. H—C≡C—H + NaNH₂

b. H—C≡C—H + CH₃Li

c. H—C≡C—H + NaOCH₃

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

(e) (CH₃)₃C–O^– + CH₃CH₂OH ⇌

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

(d)

Would amide or acetate most easily deprotonate an alcohol to make the alkoxide anion? Calculate K_eq for each possibility.

Which of the following reactions favor formation of the products? Recall that the equilibrium favors formation of the weaker acid.

Which of the following reactions favor formation of the products? Recall that the equilibrium favors formation of the weaker acid.

The acid-catalyzed hydrolysis of an ester results in the formation of an equal amount of carboxylic acid and alcohol.

(a) Design a flow chart for separating the two products.

Complete the following proposed acid–base reactions, and predict whether the reactants or products are favored.

(a)

(b)

Show how you would use extractions with a separatory funnel to separate a mixture of the following compounds: benzoic acid, phenol, benzyl alcohol, aniline

Phenols are less acidic than carboxylic acids, with values of pK_a around 10. Phenols are deprotonated by (and therefore soluble in) solutions of sodium hydroxide but not by solutions of sodium bicarbonate. Explain how you would use extractions to isolate the three pure compounds from a mixture of p-cresol (p-methylphenol), cyclohexanone, and benzoic acid.

For the following acid–base pairs, (iii) predict the favored side of equilibrium;

(e)

Ethyne (HC≡CH) has a pK_a value of 25, water has a pK_a value of 15.7, and ammonia (NH₃) has a pK_a value of 36. Draw the equation, showing equilibrium arrows that indicate whether reactants or products are favored, for the acid–base reaction of ethyne with

b. ⁻NH₂.

c. Which would be a better base to use if you wanted to remove a proton from ethyne, HO⁻ or ^-NH₂?