General Chemistry • Acid Base Equilibrium
Enter acid concentration and volume, plus base concentration. Add any number of base additions (mL). The tool finds the equivalence point and halfway point, computes pH at key volumes (0 mL, halfway, equivalence, ±1 mL around equivalence), your custom points, and plots the titration curve.
The equivalence point is the added base volume where moles of OH- added equal the initial moles of H+ (complete neutralization). The calculator finds it using Veq = (Ca x Va) / Cb.
Before equivalence, H+ is in excess, so the calculator computes remaining moles of H+ and divides by total volume to get [H+]. Then pH = -log10([H+]).
For a strong acid and strong base at 25 C, the salt formed does not hydrolyze significantly, so the solution is approximately neutral at equivalence. The calculator reports pH = 7.00 at that point.
The halfway point is the volume where the added base is half the equivalence volume (Vhalf = Veq / 2). Unlike weak-acid titrations, the halfway pH is not equal to pKa for strong acids.
Yes, you can add any number of base-added volumes as rows, and the calculator will compute pH for each custom point. It also automatically evaluates points around equivalence to show the sharp pH jump.