The hydroxyl (OH-) concentration of a solution with a pH of 8 would be 10-6 molar.

Question

Answer the following statement true (T) or false (F)

Answer 1

True

Clarify Question

• What is the key concept addressed by the question?
   o The question asks about pH.
• What type of thinking is required?
   o You are being asked to apply your knowledge of pH to calculate OH- concentration.

Gather Content

• What do you know about pH? What other information is related to the question?
   o pH is equal to -log[H+]. So a sample with a pH of 8 would have a H+ concentration of 10-8 molar. Pure water is pH 7, and the concentration of both H+ and OH- are equal at concentration of 10-7 molar. As the H+ concentration decreases the OH- concentration will increase proportionally.

Choose Answer

• Given what you now know, what information is most likely to produce the correct answer?
   o The H+ concentration of H+ has decreased 10-fold from 10-7 molar in pure water to 10-8 molar. In response the OH- concentration will increase 10-fold from 10-7 molar in pure water to 10-6 molar.

Reflect on Process

• Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
   o This question asked you to apply your understanding of pH to calculate the OH- concentration. If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did think that as pH increases the H+ concentration increases? Did you think that as the H+ concentration increases the OH- concentration also increases? Did you realize that 10-7 molar is less than 10-6 molar?