Base from the burette falls into 10.0 mL of acid in the conical flask. Choose the acid, the base, their concentrations, and the indicator, then start the flow: each drop moves the pH and extends the curve. You can also add a single drop at a time.
The panel names at the top right open and close each panel. Choose the acid, the base, and the indicator in the condition panel, then start the flow. Drag a panel by its header to move it.
The pH is found by bisection, as the value where the charge balance of the acid, the base, and the self-ionization of water is satisfied. A weak acid dissociates according to its Ka and a weak base according to its Kb, while strong acids and bases are taken as fully dissociated. Dilution by the added base is included. The values are for 25 °C with no activity correction.
The equivalence point follows a × c × V = b × c′ × V′, where a and b are how many H⁺ or OH⁻ one molecule can give: a = 2 for sulfuric acid. The screen shows the amount of H⁺ the acid can give beside the amount of OH⁻ the base added so far can give.
Choose an indicator whose range falls inside the pH jump. With a strong acid and a strong base any of them works, but titrating a weak acid with a strong base puts the equivalence point on the basic side, which is what phenolphthalein is for. With a weak acid and a weak base the jump itself is small, and no indicator can mark the end point.