How does pH relate to concentration?
There is quite a bit involved in this question. In general, the pH of an acid solution will be lower as the solution is more concentrated. For bases, the pH will be higher with more highly concentrated solutions.
Here are some important relationships to remember:
pH = -log[H+]
pOH - log[OH-]
pH + pOH = 14
Here is a video which discusses pH calculations for strong acids and strong bases.