Question

pH is the a measure of the:
A. concentration of hydrogen ions in solution
B. concentration of compounds in solution
C. concentration of OH- in solution

Answer 1

To help you answer your questions I'll say this: pH is the negative logarithm of the hydrogen ion activity (for this discussion we'll say that's almost the same thing as the concentration). This means that 0.1M HCl, for example, has a pH of 1 - the logarithm of 0.1 is -1 so the negative log is 1. Alkaline solutions have a much lower hydrogen ion concentration - I think 1M NaOH gives a pH of 14, so this is the other end of the scale. Hope this helps you answer your questions

Answer 2

pH = -log [H3O+]
H3O+ = H+

therefore, the answer is concentration of hydrogen ions in solution