Skip to main content
Ch. 25 - Amines: Structure, Reactions, and Synthesis
Mullins - Organic Chemistry: A Learner Centered Approach 1st Edition
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Not the one you use?Change textbook
All textbooksMullins 1st EditionCh. 25 - Amines: Structure, Reactions, and SynthesisProblem 47b
Chapter 24, Problem 47b

Calculate the equilibrium constant for each of the acid–base reactions shown.
b. Chemical reaction diagram showing an acid-base reaction with pKa values of -7 and 10.99 for the reactants and products.

Verified step by step guidance
1
Identify the acid and base on both sides of the reaction. Determine which species is donating a proton (acid) and which is accepting a proton (base).
Write the equilibrium constant expression for the acid-base reaction. The equilibrium constant (K_eq) is given by the formula: Keq = Kaacid1Kaacid2, where Ka values correspond to the acids on each side of the reaction.
Look up the pKa values for the acids on both sides of the reaction. Recall that Ka = 10-pKa, so you can calculate the Ka values if needed.
Substitute the Ka values into the equilibrium constant expression. Ensure that the acid on the reactant side is in the numerator and the acid on the product side is in the denominator.
Simplify the expression to determine the equilibrium constant (K_eq). This will indicate whether the reaction favors the reactants or the products.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Acid-Base Reactions

Acid-base reactions involve the transfer of protons (H+) between reactants. An acid is a substance that donates protons, while a base accepts them. Understanding the nature of the acids and bases involved is crucial for predicting the direction of the reaction and calculating the equilibrium constant.
Recommended video:
Guided course
02:49
The Lewis definition of acids and bases.

Equilibrium Constant (K)

The equilibrium constant (K) quantifies the ratio of the concentrations of products to reactants at equilibrium for a given reaction at a specific temperature. For acid-base reactions, K can be expressed in terms of the concentrations of the conjugate acids and bases. A larger K value indicates a reaction that favors product formation.
Recommended video:
Guided course
02:19
The relationship between equilibrium constant and pKa.

Conjugate Acid-Base Pairs

Conjugate acid-base pairs consist of an acid and its corresponding base that differ by a single proton. When an acid donates a proton, it forms its conjugate base, and vice versa. Recognizing these pairs is essential for calculating equilibrium constants and understanding the dynamics of acid-base reactions.
Recommended video:
2:56
Base Pairing Concept 1
Related Practice
Textbook Question

Predict the product(s) of the reactions shown.

(b)

1157
views
Textbook Question

Despite the amino group being an ortho/para director, nitration of aniline gives the meta isomer predominantly. Explain this result.

580
views
Textbook Question

Given the pKb, calculate the pKa of the conjugate acid.

(b)

1667
views
Textbook Question

Following a LiAlH₄ reduction, an IR spectrum suggested that the product was a mixture of the starting amide and the desired amine.

(b) Once separated, how could you distinguish between the amide and the amine using IR spectroscopy?

1045
views
Textbook Question

Predict the product(s) of the reactions shown.

(i)

1113
views
Textbook Question

Given the pKb, calculate the pKa of the conjugate acid.

(c)

1617
views