A couple chemistry questions.?

Question

1. If the hydroxide ion concentration of a solution is 3.68 x 10-2 M, what is the hydrogen ion concentration and pOH?

2. If the hydrogen ion concentration of a solution is 9.58 x 10-5 M, what is the pOH and hydroxide ion concentration?

3. When the pOH = 10.5, what is the hydroxide ion concentration?

4. The hydrogen ion concentration of a solution is 6.25 x 10-12 M, what is the hydroxide ion concentration, pH, and pOH?


Please, help me with these.

Answer 1

1. [OH-][H+] = 1 X 10^-14
[H+]=2.72X 10^-13
pH= -log[H+]=12.57

2. approach using the same equation as in 1. pOH is just -log[OH-]

3. to calcualte [OH-] from pOH, find 10^-pOH. On some calculators, enter the pOH, change the sign and then find the inverse log of that. For this, [OH-] = 3.16 X 10^-11

4. With what you've done in the other problems, you should be able to calculate all of these. Remember that in addition to the relationship I gave in the answer to #1, pH + pOH = 14.