Self-ionization of Water & pH
Name________________________________
15.2 Review
Period________Date____________________
Matching: On the line at left, write the letter of the best-matching definition.
_____ 1. self-ionization
a. has H3O+ concentration greater than 1 x 10−7 M
_____ 2. pure water
b. has H3O+ and OH− concentrations of 1 x 10−7 M
_____ 3. Kw - ion product constant
c. has a pH greater than 7
_____ 4. pH scale
d. describes the reaction: H2O + H2O ↔ H3O+ + OH−
_____ 5. acidic solution
e. has a pH=7;may contain ions other than H3O+& OH−
_____ 6. basic solution
f. is equal to 1 x 10−14 at 25ºC
_____ 7. neutral solution
g. describes the acidity or basicity of a solution
Short Answer: Answer the following questions in the space provided.
8. A chemist has a solution of unknown pH. Describe the most accurate way the pH can be determined.
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9. An indicator is a ____________ acid or base that is sensitive to ____________ concentration. Each
separate indicator changes ________________ over a different range of __________ values.
True or False: If the statement is true write “true.” If it is false, change the underlined word or words to
make the statement true. Write your answer on the line provided.
___________________________ 10. In the reaction H2O + H2O ↔ H3O+ + OH-, water ionizes greatly.
___________________________ 11. The ion product constant (Kw) applies to every water solution at a
given temperature.
___________________________ 12. An acidic solution contains only H3O+ ions.
___________________________ 13. A solution with a pH of 4 is acidic.
___________________________ 14. Indicators are made from neutral solutions.
___________________________ 15. When the pH of a solution decreases from 9 to 7, the [H3O+]
increases by a factor of 2.
Problems: Solve each of the problems as directed. Show all your work.
16. Based on the given information, classify the following as neutral, acidic, or basic.
a. [H+] = 1 x 10−5 M
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b. [OH−] = 1 x 10−5 M
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c. [H+] = 1 x 10−7 M
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17. Calculate the pH of a solution where [OH−] = 1 x 10−4 M.
18. Given that a solution has a pH of 3, calculate the [H3O+] and [OH−].
19. Calculate the [OH−] for an aqueous solution in which [H3O+] is 1 x 10−10 M. Is the solution acidic,
basic, or neutral? What is the pOH of the solution?
20. Determine the [H3O+] for aqueous solutions that have the following pH values.
a. 3
b. 6
c. 10
21. What is the [OH−] for solutions that have the following pH values?
a. 5
b. 9
c. 13
22. The concentration of H3O+ ions in a solution is 3.8 x 10-9 M. What is the pH of the solution? Is the
solution acidic, basic or neutral? What is the concentration of OH- ions?
23. The concentration of OH- ions in a solution is 1.6 x 10-6 M. What is the pH of the solution? Is the
solution acidic, basic or neutral? What is the concentration of H3O+ ions?
22. [OH-] = 2.6 x 10-6M ; pH=8.42 Base 23. [H3O+]=6.0x10-9M; pH=8.22 Base