b) Calculate the hydronium ion concentration, [H30+], in a solution where the hydroxide ion concentration, [0H-], equals 3.51x10 to the power of -11 M.
Can you please explain, thank you
更新1:
I messed up on the question, on letter a), just ignore the ( ] ) whee it says 0.0018 ]. I am talking about the braquet itself