To which of the following would the addition of an
equal volume of 0.60 M NaOH lead to a solution
having a lower pH? (a) water, (b) 0.30 M HCl,
(c) 0.70 M KOH, (d) 0.40 M NaNO3.
2.The attempt at a solution
the correct answer is 0.70 M KOH, and they say that by adding more OH you are producing a left shift. Okay, that's cool.
My answer is 0.30 M HCl, this is because adding a strong acid will increase H+ concentration, OH- concentration will go down, therefore pH will decrease. Why is this wrong?