Chapter 24: Solutions, Acids, and
Bases
Section 3: Acids, Bases, and Salts
Acids
Acids, Bases, and Salts
• An ACID is a substance that produces hydrogen
ions in a water solution.
• When an acid dissolves in water, H+ ions
+
interact with water molecules to form H3O
ions, known as hydronium ions.
• Acids taste sour.
• Acids are corrosive.
• An INDICATOR is an organic compound that
changes color in acids and bases.
An acid forms H3O+ due to the
excess of ________ ions?
A. H+
B. HC. OH-
Acids have excess ______ ions?
A. hydroxide
B. water
C. hydronium
A hydronium ion, H3O+ contains
_______.
A. 3 helium atoms and 1 oxygen atom
B. 3 hydrogen atoms and 1 oxygen atoms plus
something else
C. 1 hydrogen atom and 3 oxygen atoms
D. 3 hydrogen atoms and 1 oxygen atom
Acids, Bases, and Salts
3
INDICATORS
• An indicator is an organic compound
that changes color in acids and bases.
• Litmus is an example of an indicator
• Litmus paper is paper soaked in litmus
• Sometimes called pH paper, or
pHyronium paper
An acid will change the color
of litmus, an indicator.
A. True
B. False
Acids, Bases, and Salts
3
• Many foods
contain acids.
Acids, Bases, and Salts
Bases
• Bases can be defined in two ways.
• Any substance that forms hydroxide
ions, OH― in a water solution is a base.
• A base is any substance that accepts H+ from acids.
A base has an excess of _____
ions?
A. H3O+
B. OHC. H2O
Bases have excess ______ ions?
A. hydroxide
B. water
C. hydronium
A hydroxide ion, OH- has ____.
A. 1 oxygen atom, 1 hydrogen atom with another
element missing
B. 1 oxygen atom and 1 hydrogen atom
C. 1 oxygen atom and 1 helium atom
D. this ion does not exist.
Acids, Bases, and Salts
3
Properties of Bases
• In solution, bases feel slippery and
have a bitter taste.
• Bases react with indicators to produce
changes in color.
Acids, Bases, and Salts
You probably are
familiar with
many common
bases because
they are found in
cleaning products
used in the home.
Soaps and detergents are ____.
A. acids
B. bases
Acids, Bases, and Salts
Solutions of Acids and Bases
Dissociation of Acids
• When an acid dissolves in water, the negative
areas of nearby water molecules attract the
positive hydrogen in the acid.
• The acid dissociates into ions and the hydrogen
atom combines with a water molecule to form
hydronium ions.
Acids, Bases, and Salts
Dissociation of Bases
• The positive areas of nearby water
molecules attract the - OH of the base.
• The base dissociates into a positive ion and a
negative ion.
• Unlike in acid dissociation, water molecules do
not combine with the ions formed from the base.
H3O+ + OH-  _______
A. H2O
B. 2H2O
C. No reaction occurs
Acids, Bases, and Salts
NEUTRALIZATION
• Neutralization is a chemical reaction between
an acid and a base that takes place in a
water solution.
Acids, Bases, and Salts
Acid-Base Reactions
acid + base
salt + water
• A SALT is a compound formed when the
negative ions from an acid combine with the
positive ions from a base.
Question 1
What does an acid produce in solution?
A. H3OB. H3O+
C. H+
D. H-
Question 1B
What does an acid Form in solution?
A. H3OB. H3O+
C. H+
D. H-
Section Check
Question 1
What does an acid produce in solution?
Answer
An acid produces hydrogen ions in solution,
which interact with water molecules to form
hydronium ions.
Which changes color in acids
and bases?
A. ammonia
B. antacid
C. detergent
D. litmus
Section Check
Answer
The answer is D. Litmus is an indicator that
turns blue in bases and red in acids.
Any substance that forms
_______ in a water
solution is a base.
A. H3OB. OHC. H++
D. H2O
Section Check
Answer
The answer is B. A base is any substance that
forms hydroxide ions in water.