Required practical 9: Titration curve

Describe the experiment

• transfer 25cm of acid to a flask using a volumetric pipette

• Measure the initial PH with a ph meter

• Add alkali in small amounts and note the initial and final volume

• Store mixture TO EQUALISE THE PH

• Repeat but near the end add smaller volumes of alkali

What is the half neutralisation volume

• [HA]=[A-]

• Ka=[H=]

• PKA=pH

With a titration curve how do we find PH?

• if we know the Ka we can work out PH at half the equivalence point

How do we know the PH of a weak acid

• half neutralisation = pKa