posted by jessie on .
which solution has the highest concentration of hydroxide ions?
i know the answer is 7 but why is it seven? would it be different if it said hydronium ions?
Who told you the correct answer is 7.00? That isn't right.
Reason through it.
Low pH means high pOH (since pH + pOH = 14) and that means high H^+. So for high OH^- we want a high pH which means a low pOH and that is a high OH^-. If you don't like that method, go through and calculate the concn of OH^- for each.
pH = 7.93. pOH = 6.07. OH^- = 8.5E-7
pH = 7.00. pOH = 7.00. OH^- = 1.00E-7
pH = 3.21. pOH = 10.79. OH^- = 1.62E-11
Note that for these three examples I've done, pH 7.93 has a higher OH than the other two, (including pH = 7.00).
oh, i see, it was a question on my chem test that i got wrong, the answer sheet said 7. this teacher is always giving questions with wrong answers, its very frustrating.