Ch.15 - Acid and Base EquilibriumSee 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

In 1923, Johannes Brønsted and Thomas Lowry developed a new set of definitions for acids and bases. 

Understanding Bronsted-Lowry Acids and Bases

According to Brønsted and Lowry, an acid was classified as a proton donor while a base was a proton acceptor. 

Concept #1: Discussing Brønsted – Lowry Acids and Bases. 

Example #1: Write the formula of the conjugate base for the following compound: HSO4-

 

Example #2: Write the formula of the conjugate acid for the following compound: V2O52-

Practice: Write the formula of the conjugate base for the following compound:

H2Se

Practice: Write the formula of the conjugate for the following compound:

NH2NH2

Brønsted – Lowry Reactions

Brønsted – Lowry acid and base reactions create products that are conjugates of the reactants. 

Example #3: Identify the acid, base, conjugate acid and conjugate base in the following reactions:

     HF (aq)  +  H2O (aq)  ⇌ F (aq)  +  H3O+ (aq) 

Example #4: Identify the acid, base, conjugate acid and conjugate base in the following reactions:

     CN (aq)  +  H2O (aq)  ⇌  HCN (aq)  +  OH (aq)  

Practice: Which of the following is a Bronsted-Lowry acid?

Practice: Determine the chemical equation that would result when carbonate, CO32-, reacts with water.

Additional Problems
Some polyatomic ions containing hydrogen can act as Brønsted-Lowry acids or bases. Write a balanced equation for the reaction that occurs when the hydrogen carbonate ion behaves as a Brønsted-Lowry acid in water. a. HCO3–(aq) + H2O(l) ⇌ H2CO3(aq) + H3O+(aq) b. CO32–(aq) + H2O(l) ⇌ HCO3–(aq) + OH–(aq) c. HCO3–(aq) + H2O(l) ⇌ CO32–(aq) + H3O+(aq) d. HCO3–(aq) + H2O(l) ⇌ H2CO3(aq) + OH–(aq) e. H2CO3(aq) + H2O(l) ⇌ HCO3–(aq) + H3O+(aq)    
Complete this Bronsted-Lowry reaction, placing each product by its appropriate label. HCO3- + NO2- ⇌ ------- acid + ------ base
What is the name of a proton donor in a reaction? A) Arrhenius acid             B) Arrhenius base                   C) Bronsted-Lowry acid D) Bronsted-Lowry base             E) Lewis base
A Bronsted-Lowry acid is always a Lewis acid a.True b. False
According to the Bronsted-Lowry definition of acids and bases, what is the conjugate base of HBrO2? A. H2BrO2 B. BrO2- C. H2O D. OH- E. H3O+
Complete the following questions about Bronsted-Lowry acids and bases. a) Classify each of the following acids as strong or weak: HF, H 2SO4, HNO2, HBr, HClO4, CH3COOH, H3PO4               b) Classify each of the following bases as strong or weak: NaOH, NH 3, HCO3-, CH3NH2         c) Write an equation that shows how a generic acid, HA, ionizes (dissociates) in water.     d) Write an equation that shows how a generic base, B, ionizes (dissociates) in water.
Which statement is correct for this reaction? HS – (aq) + NH4 + (aq) → H2S (g) + NH3 (g) a. HS – acts as an acid b. NH4 + acts as a base c. HS – is a proton donor for NH4 + d. NH4 + is a proton donor for HS
Identify the Bronsted-Lowry acids, Bronstead-Lowry bases, conjugate acids, and conjugate bases in the following reactions: (a) C2H3O2-(aq) + H2O (l) ⇌ HC2H3O2 (aq) + OH-(aq)   (b) H2CO3 (aq) + H2O (l) ⇌ H3O+(aq) + HCO3-(aq)   (c) C5H5NH+(aq) + H2O (l) ⇌ C5H5N (aq) + H3O+(aq)   (d) HNO3 (aq) + H2O (l) → H3O+(aq) + NO3-(aq)
Identify the Bronsted-Lowry acids and bases in the following reactions: (a) HC2H3O2 (aq) + NH3 (aq) ⇌ C2H3O2-(aq) + NH4+(aq)   (b) 2 HCl (aq) + Ca(OH)2 (aq) → 2 H2O (l) + CaCl2 (aq)  
Proton acceptor is an abbreviated definition of:       A) Lewis acid B) Arrhenius acid C) Br∅nsted-Lowry acid D) Lewis base E) Br∅nsted-Lowry base 
Which one of the following is a Br∅nsted-Lowry acid?      A) HF B) HNO 2 C) CH 3COOH D) (CH 3) 3NH + E) all of the above
In the following reversible reaction the Br∅nsted acids are (in both the forward and reverse directions) ________.             HCO 3 −(aq) + OH −(aq) ⇌ CO 3 2 −(aq) + H 2O      A) OH − and H 2O B) HCO 3 − and CO 3 2 - C) HCO 3 − and H 2O D) OH − and CO 3 2 − E) H 2O and CO 3 2 −
Complete these Brønsted-Lowry reactions.a. HS- + H+ →b. HS- + OH- → 
According to the Bronsted-Lowry definition, which chemical in the following reaction is the acid?H3PO4 + H2O → H3O+ + H2PO4-         a. H2Ob. H3O+c. H3PO4d. H2PO4-e. None of the above  
According to the Bronsted-Lowry definition, which chemical in the following reaction is the base?H3PO4 + NH3 → NH4+ + H2PO4-a. NH3b. NH4+c. H2PO4-d. H3PO4e. None of the above 
Rank the following four acids in order of increasing bronsted acidity : H2F+, CH3OH, (CH3)2OH+, CH3SH2+
HI(aq) + H2O(l) ⇌ H3O(aq) + I-(aq)Identify each as either a: Bronsted-Lowry acid, Bronsted-Lowry base, conjugate acid, or conjugate base.
Consider the reactions below:a. HBr (aq) + H2O (l) → H3O+ (aq) + Br - (aq)b. HCl (g) → H + (g) + Cl - (g)c. H- (aq) + H2O (l) → H2 (g) + OH - (aq)d. Mg(OH)2 (aq) → Mg 2+ (aq) + 2OH - (aq) e. OCl- (aq) + H2O (l) → HOCl (aq) + OH - (aq)Which of these species are Arrhenius acids?Which of these species are Arrhenius bases?Which of these species are Lowry Bronsted acids?Which of these species are Lowry Bronsted bases?
Label each reactant and product in this reaction as a Bronsted acid or base.
Acid-base reactions, according to Brønsted-Lowry, can be considered to involve the transfer of ____.  a) anions b) electrons c) protons d) OH e) it depends on the molecules.
Complete these Bronsted-Lowry reactions. A) HPO42- + H+ ⇌  B) HPO42- + OH- ⇌
Given the balanced equation representing a reaction: HSO4-(aq) + H2O(l) → H3O+(aq) + SO42-(aq) According to one acid-base theory, the H2O(l) molecules act as a. a base because they accept H+ ions b. a base because they donate H+ ions c. an acid because they accept H+ ions d. an acid because they donate H+ ions
In the reaction: NH3 + HCl → NH4+ + Cl - The NH3 acts as a. a Bronsted acid, only b. a Bronsted base, only c. both a Bronsted acid and a Bronsted base d. neither a Bronsted acid nor a Bronsted base
Label each reactant and product in this reaction as a Bronsted acid or base. H2Y- + H2Z- ⇌ H3Y + HZ2-
Label each reactant and product in this reaction as a Bronsted acid or base.
For F−, write an equation that shows how the anion acts as a base.Express your answer as a chemical equation. Identify all of the phases in your answer.
For ClO2−, write an equation that shows how the anion acts as a base.Express your answer as a chemical equation. Identify all of the phases in your answer.
Explain the following observations: (a) NH 3 contains no ions, and yet its aqueous solutions are basic
Which of the following statements is false?(a) An Arrhenius base increases the concentration of OH- in water.(b) A Brønsted-Lowry base is a proton acceptor.(c) Water can act as a Brønsted–Lowry acid.(d) Water can act as a Brønsted–Lowry base.(e) Any compound that contains an –OH group acts as a Brønsted-Lowry base.
Which statement is correct for this reaction?PH3(aq) + NH4+(aq) → PH4+(aq) + NH3(g)A) PH3 acts as an acid.B) NH4+ acts as a base.C) PH3 is a proton donor for NH4+.D) NH4+ is a proton donor for PH3.
Classify each of these compounds as a Bronsted-Lowry acid, a Bronsted-Lowry Base, or neither.H2SO4HBrH3PO4(CH3)3NCH3NH2NH3KClCHCl3
According to the Bronsted-Lowry definition, what happens in an acid-base reaction? a. An acid transfers a proton to a base.b. A base transfers a proton to an acid.c. A base donates an electron pair to an acid.d. An acid donates an electron pair to a base.e. An acid and a base always react to form salt and water.
Rank the given compounds based on their relative Bronsted acidities. (Strongest Bronsted acid to weakest Bronsted acid). H - SH, H - F, H - Br, H - I, H - OH, H - CH3, H - NH2
Complete this equation to show how pyridine acts as bronsted-lowry base in water. C5H5N + H2O →
Complete this Bronsted-Lowry reaction, placing each product by its appropriate label.
Complete this Bronsted-Lowry reaction, placing each product by its appropriate label.
Write an equation showing CH3OH reacting as a base with HCl. Express your answer as a chemical equation. 
Write an equation showing CH3OH reacting as an acid with NH3. Express your answer as a chemical equation. 
Complete these Bronsted-Lowry reactions.HPO42- (aq) +    H+(aq) ⇌HPO42- (aq) + OH-(aq) ⇌
Which of the following is never a Bronsted-Lowry base in an aqueous solution? (a) hydrogen bromide, HBr(g) (b) sodium dihydrogen phosphate, NaH2PO4(s) (c) sodium phosphate, Na3PO4(s) (d) ammonia, NH3(g) (e) sodium bicarbonate, NaHCO3(s) 
Complete this Brønsted-Lowry reaction, placing each product by its appropriate label.HSO4- +BrO-Acid? + Base?