http://www.ck12.org Chapter 21. Acids and Bases
TABLE21.3: Acid-Base Definitions
Type Acid Base
Arrhenius H+ions in solution OH−ions in solution
Brønsted-Lowry H+donor H+acceptor
Lewis electron-pair acceptor electron-pair donorLesson Summary
- Acids and bases have distinct properties. Both are electrolytes and turn indicators a specific color. Acids
taste sour, while bases tend to taste bitter. Solutions of acids and bases react with each other to give a neutral
solution. - Arrhenius acids yield H+ions in aqueous solution. Arrhenius bases yield OH−ions in aqueous solution.
- Brønsted-Lowry acids are proton donors, while Brønsted-Lowry bases are proton acceptors. A Brønsted-
Lowry acid-base reaction consists of two conjugate acid-base pairs. - Lewis acids are electron-pair acceptors, while Lewis bases are electron-pair donors.
- The Arrhenius definition of acids and bases is the narrowest definition, while the Lewis definition is the
broadest.
Lesson Review Questions
Reviewing Concepts
- Which statement below is true? Explain.
a. All Arrhenius bases are also Brønsted-Lowry bases.
b. All Brønsted-Lowry bases are also Arrhenius bases. - Classify each of the following as an Arrhenius acid, Arrhenius base, or neither.
a. LiOH
b. HClO 4
c. H 2 C 2 O 4
d. CH 3 COOH
e. Sr(OH) 2
f. CH 4 - What does it mean to say that a substance is amphoteric?
- What must be true about a certain covalent bond in order for a hydrogen atom to be ionizable?
- In order to be a Brønsted-Lowry base, a molecule or ion must have a lone pair of electrons. Explain why this
is true.
Problems
- Identify each reactant in the following reactions as an acid or a base according to the Brønsted-Lowry theory.
a. HIO 3 (aq)+H 2 O(l)⇀↽IO− 3 (aq)+H 3 O+(aq)
b. F−(aq)+HClO(aq)⇀↽HF(aq)+ClO−(aq)
c. H 2 PO− 4 (aq)+OH−(aq)⇀↽HPO^24 −(aq)+H 2 O(l)