Suppose you were titrating approximately 0.1 m hcl solution with standardized naoh solution (0.0989m). in your lab manual, you were instructed to add 15.00 ml hcl, but you accidentally added 25.00 ml instead. how would this mistake affect the ph at equivalence point?

Answer is: will not change the pH of equivalence point.

Balanced chemical reaction: HCl + NaOH → NaCl + H₂O.

In this reaction pH of equivalence point will be always 7.

Equivalence point is the point which there is stoichiometrically equivalent amounts of acid and base.  

Chemist can draw pH curve (graph showing the change in pH of a solution, which is being titrated) for titration and determine equivalence point.

Near equivalence point indicator should change color, so we must pick indicator who change color near pH of equivalence point.