What is the PH of a solution whose [H+] is 0.0007

To determine the pH of the solution. All you would have to do is use the equation:

pH = - log (H3O^+)

pH = - log (0.0007)

pH = 3.15.

Note that H + and H3O + are the same, it is more accurate to say H3O + because of how the H2O molecules become after receiving the additional proton.