PROBLEM SET
Acids, Bases, and pH
These questions and activities come from a variety of sources: your textbook, other books that I have, study guides,
and old homeworks, labs, and exams. They are provided to give you an idea of the types of questions you can expect
to see on exams. These are not to be turned in for a grade, though I am happy to go over your answers with you.
Important Vocabulary Terms: Write out definitions for each of the following terms:
a. dissociation
b. acid
c. acidic solution
d. base
e. basic solution
f. pH scale
g. buffer
Multiple Choice: Select the best answer from the choices provided:
1. Look at the figure to the right, showing the pH
values of some familiar aqueous solutions. What
is the difference between H+ concentration in an
acidic solution such as lemon juice (pH 2) and a
basic solution such as household bleach (pH 13)?
A. The H+ concentration of household bleach is
higher than the H+ concentration of lemon
juice by a factor of 1011 (100 billion).
B. The H+ concentration of lemon juice is
higher than the H+ concentration of
household bleach by a factor of 11.
C. The H+ concentration of lemon juice is
higher than the H+ concentration of
household bleach by a factor of 1011 (100
billion).
2. Identify all correct statements about the ionization of water. Check all that apply.
A. Because the dissociation of water is reversible and produces equal numbers of short-lived
OH- and H+, it has little effect on the chemistry of life.
B. Water ionizes to form hydroxide and hydronium ions.
C. Buffers are substances that minimize the concentrations of OH- and H+ in solutions.
Additional problems: Write your answers in the spaces provided.
1. Write out the chemical equation for the dissociation of water.
2. Pure water has a neutral pH.
•
Why?
•
What is water’s pH value?
3. Both NaCl and HCl are ionic compounds. When they are added to water, they form a
solution by dissociating into their individual ions.
•
Which of these — NaCl or HCl — would you expect to change the pH of pure water?
•
Why?
•
Would the solution become more acidic or more basic?
•
Would the pH increase or decrease?
4. Use your knowledge of pH, acids and bases to answer the following questions. Mark your
answer with a checkmark (✔).
a. Which of the following pH values indicates a solution containing a weak acid?
____ 1.72 ____ 3.75
____ 2.00
____ 6.27
____ 2.7 ____ 8.3
____ 4.2
____ 10.8
____ 14.0
____ 1.72 ____ 3.75
____ 7.00
____ 5.00
____ 6.38
____ 2.2 ____ 4.7
____ 11.1
____ 13.7
____ 2.70 ____ 4.65
____ 5.00
____ 7.00
b. Which of the following pH values indicates a solution containing a weak base?
c. Which of the following pH values indicates a solution containing a strong acid?
d. Which of the following pH values indicates a solution containing a strong base?
e. Of solutions with the following pH values, which one is neutral?
5. The table below gives pH ranges for a variety of body fluids. Indicate whether these fluids are
acidic, basic or neutral.
Fluid:
saliva
bile
urine
gastric juices
blood
pancreatic juices
pH range:
5.5 – 6.9
7.8 – 8.6
5.5 – 6.9
1.6 – 1.8
7.35 – 7.45
7.5 – 8.0
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6. Which of the body fluids listed above has the highest concentration of H+?
7. Compared with a basic solution at pH 9, the same volume of an acidic solution at pH 4 has
____ times as many hydrogen ions (H+).
8. Complete the concept map below:
pH
measures concentration of
regulated by
molecules called
which will
+
if [H ] > [OH ]
+
if [H ] = [OH ]
+
if [H ] < [OH ]
pH < _____
pH = _____
pH > _____
and is therefore called
and is therefore called
and is therefore called
if solution is too acidic
if solution is too basic