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Ch.15 - Acid and Base EquilibriumWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch.17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds
Acids Introduction
Bases Introduction
Binary Acids
Amphoteric Species
Arrhenius Acids and Bases
Bronsted-Lowry Acids and Bases
Lewis Acids and Bases
The pH Scale
Ka and Kb
pH of Strong Acids and Bases
Ionic Salts
pH of Weak Acids
pH of Weak Bases
Diprotic Acids and Bases
Diprotic Acids and Bases Calculations
Triprotic Acids and Bases
Triprotic Acids and Bases Calculations
Additional Guides
Conjugate Acids and Bases

The set of definitions for Bronsted-Lowry Acids and Bases are credited to Johannes Bronsted and Thomas Lowry in 1923.

Understanding Bronsted-Lowry Acids and Bases

Concept #1: Bronsted-Lowry Acids and Bases are defined by their donation and acceptance of hydrogen ions respectively.

Example #1: Identify each compound as either Bronsted-Lowry acid or base.

a) NH4 ____________   c) CH3NH __________

b) LiH ___________         d) H2Te ____________

Concept #2: Bronsted-Lowry Acids and Bases Concept 2

Bronsted-Lowry Acids and Bases represent a broader view of acids and bases that don't require an aqueous environment.

Example #2: Identify each compound as either Bronsted-Lowry acid/base, Arrhenius acid/base or both.

a) H2CO3 _______________     d) Sr(OH)2 _______________

b) CH3NH _______________ e) HF ___________________

c) KNH2 _________________  f) CaH __________________

Concept #3: Bronsted-Lowry Acids and Bases Concept 3

Example #3: Provide formulas of the conjugates for each of the following compounds.

a) NH2NH2 ______________________

b) HCHO ______________________

c) HSO4(base) _________________

d) HClO ______________________

A conjugate acid is obtained by adding a hydrogen ion and a conjugate base is obtained by removing a hydrogen ion. 

Practice: Identify conjugate acid and conjugate base in the following reaction.

                                                    H2PO4 (aq) + H2O (l) ⇌ HPO42 (aq) + H3O+ (aq)

a) HPO42 (conjugate acid), H3O+ (conjugate base) 

b) HPO42 (conjugate base), H3O+ (conjugate acid)

c) H2PO4 (conjugate acid), H2O (conjugate base)

d) H2PO4 (conjugate base), H2O (conjugate acid)

Practice: In the following reaction, label Bronsted-Lowry acid and base, along with conjugate acid and base.


H2C6H6O6 (aq) + H2O (l) ⇌ HC6H6O6 (aq) + H3O (aq)


Strength of Conjugate Acids and Bases

To fully understand the strength of acids and bases relies on also understanding their conjugates.

Concept #4: There is an inverse relationship in strength between acids/bases and their conjugates.

Concept #5: Weak species will create stronger conjugates.

Example #4: Which of the following acids have relatively strong conjugate bases?

a. HBrO4                           b. HCN                         c. HNO3                        d. HClO4 

Practice: Which of the following is the strongest base?

a. NO3                         b. F                              c. Cl                             d. ClO4                         e. H2O

Practice: Which of the following bases will have the weakest conjugate acid?

a. CH3COOH                b. KOCH3                      c. CH3NH2                     d. NH4OH                            e. LiOH