1. Standardizing a Solution Lab
NaOH and KHP

2. Standardizing a Solution
Standardize means to determine a precise and
accurate concentration
- Normally we could mass out a desired solute to make a solution
Why can’t we do it with NaOH???
NaOH is deliquescent so we can’t trust the mass value.
Deliquescent means = tendency to absorb moisture from the air

3. Deliquescent NaOH

4. What to do??? Standardization by Titration
Dilute then titrate against a primary standard
In this case, KHP (weak acid) can be accurately and precisely weighed
Potassium hydrogen phthalate, simply KHP
Solid, air-stable, not hygroscopic
Molecular Mass = g/mol

5. Procedure Discussion:
Complete the prelab exercises.
We will complete Method 1 procedure.
In our procedure, a known volume of the primary std KHP solution will be “titrated” with NaOH until a color change is noticed
End point is indicated by the color change
Equivalence Point will be determined graphically
End Point = Equivalence Point

6. What is the End Point?

7. What is the Equivalence Point?
point at which an added titrant is stoichiometrically equal to the number of moles of substance present in the sample
Strong Base NaOH
Weak Acid KHP

8. Conduct Procedure

9. Download Shared Data
Go to Wikispace, download/save 2nd Derivative Plot for Titration 1 and Titration 2
Analyze the plot for the equivalence point
Record in mL of base, NaOH on data table

10. Why the derivative?

11. Complete the Data Analysis