Lab #14B: Acid-Base Titration CurvesPurposeIn this experiment you will use a volumetric titrationto determine the titrationcurve for a weak acid. You will determine the equivalence pointfor the acid andcalculate the molar concentration of the acid solution. MaterialsChemicalsAmmonia solution- NH3(1M) (SDS)VinegarEquipment from HomeDistilled waterCell phone cameraClear tape to secure syringeMicrosoft Excel or anotherspreadsheet programEquipment from KitGoggles & gloves50 mL & 10 mL graduatedcylinders250 mL & 150 mL beakerspH meter & buffer solutionssyringe and stopcockfunnelpipettesIntroductionAcid-Base titration curvesare graphs that show the successive pH values thatoccur during the titration of a base with an acid or an acid with a base. Thegeneral purpose of a titration is to determine the amount of a particular substancein a sample. An acid-base titration curve can be used to find the equivalence point,which is the point where equal stoichiometric moles of been added. The volumeof base added (titrant) at the equivalence point can be used to find the moles ofacid in an unknown solution. An Acid-Base titration curve will vary depending on the strength of the acids andbases. When a strong acid is titrated with a strong base, the curve will risesharply and have an equivalence point at pH = 7. If a weak acid is titrated with astrong base or a weak base is titrated with a strong acid the titration curve isunique because one of the ions in the salt formed will often hydrolyze in water.For a weak acid, the equivalence point will be at a pH higher than 7. For a weakbase it will be lower than 7. Volumetric TitrationLab #151
A titration is a process used to determine the volume of a standard solution that isneeded to react with a given amount of another substance. In this experiment,your goal is to determine the molar concentration of an acid solution byconducting titrations with a base of known concentration. You will be testing aweak acid found in vinegar, acetic acid (HC2H3O2). You will use ammonia (NH3)solution as your base of known concentration. The reaction equation is shownbelow in net ionic form.HC2H3O2(aq) + NH3(aq) ↔NH4+(aq) + C2H3O2–(aq)Notice that a double arrow is used since this is a reversible reaction, orequilibrium, since it is a weak acid. A weak acid is one that doesn’t completelydissociate in solution.