Jul 12, 2011 · The [OH-] of a solution is 1.0 x 10-3 M. What is the pH of the solution? 1) 3.00 2) 11.00 3) –11.00 My calculator is a Texas Instruments 30X 2S. I just learned how to use -log for [H3O+] of tomato juice is 2 x 10-4M. With the problem above with [OH-] I'm having trouble entering into my calculator to get the answer. I've been using a PH graph in my book and figuring it out. For the Kw I ...