How do you solve this chemistry problem? Need HELP?

[H+] molarity chemistry calculation problem . Need help urgently!?

• Hi, could someone please help solve and explain this chemistry problem to me. Thanks! The problem is: Calculate the [H+] in the following aqueous solution of 2.5x10^-3 M of Barium Hydroxide solution Note: the answer is 2x10^-12 M but I really need someone to SHOW me how to get this because I keep getting it wrong. Thanks again!

• Answer:

  Barium Hydroxide is Ba(OH)2 which completeley dissociates to Ba2+ and 2OH- in solution As you can see, the number(concentration) of OH- is twice the number(concentration) of Ba(OH)2 which will be 2 x 2.5x10^-3 M = 5 x 10^-3 M Now we know the OH- concentration, but we want the [H+] concentration. We know that in an aqueous solution, [H+]x[OH-] = 10^-14 Therefore, [H+] = 10^-14 / [OH-] = 10^-14 / 5 x 10^-3 = 2 x 10^-12 M So the answer is 2x10^-12 M