Skip to main content
Ch.17 - Acids and Bases
Tro - Chemistry: A Molecular Approach 6th Edition
Tro6th EditionChemistry: A Molecular ApproachISBN: 9780137832217Not the one you use?Change textbook
All textbooksTro 6th EditionCh.17 - Acids and BasesProblem 92b
Chapter 17, Problem 92b

Write equations showing how each weak base ionizes water to form OH–. Also write the corresponding expression for Kb. b. C6H5NH2

Verified step by step guidance
1
Identify the weak base and its formula. In this case, the weak base is aniline, which has the chemical formula C6H5NH2.
Write the ionization reaction of the weak base with water. Aniline reacts with water to form aniline ion and hydroxide ion: C6H5NH2 + H2O ⇌ C6H5NH3+ + OH-.
Identify the products and reactants in the ionization reaction. Reactants are C6H5NH2 and H2O, and the products are C6H5NH3+ (anilinium ion) and OH- (hydroxide ion).
Write the expression for the base ionization constant (Kb). The Kb expression is derived from the equilibrium concentrations of the products and reactants: Kb = [C6H5NH3+][OH-] / [C6H5NH2].
Note that in the Kb expression, the concentration of water is typically omitted because it is a liquid and its concentration remains relatively constant.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
1m
Was this helpful?

Key Concepts

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

Weak Bases

Weak bases are substances that partially ionize in water to produce hydroxide ions (OH-). Unlike strong bases, which completely dissociate, weak bases establish an equilibrium between the undissociated base and its ions in solution. This characteristic is crucial for understanding their behavior in aqueous solutions and their effect on pH.
Recommended video:
Guided course
00:51
ICE Charts of Weak Bases

Ionization of Water

The ionization of water refers to the process where water molecules dissociate into hydrogen ions (H+) and hydroxide ions (OH-). This equilibrium is essential for understanding how weak bases interact with water, as they accept protons from water, leading to the formation of OH- ions. The extent of this ionization is influenced by the strength of the base.
Recommended video:
Guided course
02:22
Auto-Ionization and Kw

Base Dissociation Constant (Kb)

The base dissociation constant (Kb) quantifies the strength of a weak base in solution. It is defined as the equilibrium constant for the reaction of the base with water, representing the ratio of the concentration of the products (OH- and the conjugate acid) to the concentration of the undissociated base. A higher Kb value indicates a stronger weak base, as it suggests a greater degree of ionization.
Recommended video:
Guided course
03:50
Characteristics of Ka and Kb
Related Practice
Textbook Question

Caffeine (C8H10N4O2) is a weak base with a pKb of 10.4. Calculate the pH of a solution containing a caffeine concentration of 455 mg/L.

3290
views
4
rank
Textbook Question

For each strong base solution, determine [OH–], [H3O+], pH, and pOH. c. 1.9×10–4 M KOH

295
views
Textbook Question

Write equations showing how each weak base ionizes water to form OH–. Also write the corresponding expression for Kb. c. C2H5NH2

905
views
Textbook Question

Determine the pH of a solution that is 3.55% KOH by mass. Assume that the solution has density of 1.01 g/mL.

Textbook Question

Write equations showing how each weak base ionizes water to form OH–. Also write the corresponding expression for Kb. a. CO32–

951
views
Textbook Question

Determine the [OH–], pH, and pOH of a 0.15 M ammonia solution.

1581
views
1
rank