Titration Calculations

A titration calculation converts the titrant's known volume and molarity to moles at the endpoint, applies the balanced reaction's mole ratio to find moles of the unknown, then divides by the unknown sample's own volume to find its molarity.

A 50.00-mL HCl sample is titrated to its endpoint by 35.23 mL of 0.250 M NaOH. Multiplying 0.03523 L by 0.250 mol/L gives about 0.00881 mol NaOH delivered. Because HCl and NaOH react in a 1-to-1 ratio, the sample also contained about 0.00881 mol HCl at the start. Dividing 0.00881 mol by the sample's own 0.05000-L volume gives an HCl concentration of about 0.176 M.