I just don’t understand why the answer is
[H+]= 4.0 x 10-15 moldm-3
pH= 14.40
The question is:
Calculate the pH at 25 C of 2.5M NaOH
The question before that (if it’s any indication of what to do ) is: calculate the pH at25C of 2.00 M HCl and the answer for that is -0.30