A Method for a Titration
Next, using the weigh-by-difference method, measure a sample of potassium hydrogen phthalate, KHP (1) into a clean, dry 125-mL Erlenmeyer flask and dissolve it in 40 mL of water. KHP (MWT = 204.22 g/mol) is a monobasic acid that contains one mole of neutralizable hydrogen per mole of compound. Therefore, this monobasic acid reacts 1:1 stoichiometrically with sodium hydroxide, Equation 1.
Equation 1
To determine the mass of KHP required for the titration, you should first determine the number of moles of NaOH in approximately 15 mL of your titrant. Let�s say that your NaOH titrant concentration is 5.00 M. How many moles of NaOH would be present in 15.0 mL?
5.00 moles/L X 0.0150 L= 7.50 X10-2 moles of NaOH.
Since sodium hydroxide reacts 1:1 with the KHP acid this also the number of moles of KHP needed for a complete reaction and neutralization. The grams required can be obtained by multiplying the moles of NaOH by the molecular weight of KHP.
7.50 X 10-2 moles X 204.22 g KHP/ 1 mole = 15.3 g KHP