1. I-Solubility Product: Acid-Base Volumetric Analysis
Dr. Prem D. Sattsangi
Copyright © 2009

2. What is KHT? KHT is short for Potassium Hydrogen Tartarate.
It is mono-potassium salt of TARTARIC ACID.
It is only slightly SOLUBLE.
The “2 OH” groups are “cis” and written on the left side.
The soluble KHT ionizes to give HT- and K+ ions
Ksp (KHT) = [K+ ] [HT- ] = ?

3. #1-A Solubility Product Experiment
Record Room temperature at the top of each experiment
1. Solubility of KHT in presence of a common ion, [K+]
2. Solubility of KHT in distilled water
3. Determination of an Unknown Potassium concentration

4. #2 Section-1. Solubility of KHT in presence of a common ion, [K+]
Each student will be assigned a concentration of KNO3 from M, 0.060, M ….to M.
PROCEDURE:
Calculate mass of KNO3 needed to prepare 100 mL of M solution. [n = M x V; Atomic masses (K = 39.09, N = 14.01, O = 16.00)].
(= 1.92 g) FW KNO3 = 101.1
0.190 mol x L x g = g
1 L mol
H. it I.

5. #2b-Preparing solution
Weigh on the table top balance. [+/ g]. Add it to the 100 mL Volumetric flask and make it up to the mark using STOCK-KHT saturated solution. POUR SLOWLY through Funnel.
AVOID OVER FILLING
Stopper securely. Shake by inversion rotation occasionally.
Allow time to equilibrate Proceed with Section 2 of the experiment.

6. #3 Section-2. Solubility of KHT in distilled water, Filtration of saturated KHT
PROCEDURE:
Set up a filtration apparatus. Moisten the filter paper with Saturated KHT solution.
Place a 150/250 mL beaker underneath the funnel. Do not fill the filter paper to the top. Leave ~ 1 cm empty. Allow to filter. As filtration proceeds, add more solution.
Filter all of it.

7. #4 Section-2 Titration in duplicate of the Filtrate
Pipet mL of filtrate in mL Erlenmeyer flasks A, B.
Add 2 drops phenolphthalein and a small magnetic bar.
Set to stir gently.
Titrate Flask “A” to a faint pink Titrate Flask “B” to a faint pink
CALCULATE SOLUBILITY
NaOH KHT  NaKT + H2O
M ? M
____mL mL
H. it I.

8. #5 Section-1 Solubility of KHT Filtration of [K+] in KHT(satd
#5 Section-1 Solubility of KHT Filtration of [K+] in KHT(satd.), Titration, and Calculation
These are exactly the same as done before for Section 1.
For the assigned [K+], write, NaOH (mL) and [HT-] on the BLACK BOARD.
A manual plot of the graph is due on the next turn.
This graph will be used by you to figure out the [K+] in the U.K.
CALCULATE SOLUBILITY
NaOH KHT  NaKT + H2O
M ? M
____mL mL

9. #6 Section-1. Solubility of KHT in Presence of [K+] added
Data:
[K+] [KHT]
Graph will be used for U.K.
If the solubility of KHT in presence of (U.K.) = M;
[K+] added = M

10. #7 Section-3.Determination of an Unknown [K+] Filtration, Titration, and Calculation
A U.K. solution containing KNO3 and KHT (saturated) will be supplied in a 125 mL Erlenmeyer.
Filtration, Titration in duplicate, and Calculation are exactly the same as done before for Section 1.
RESULT:
Extrapolate the Solubility of KHT on the graph to find the [K+] value for the U.K.
A Report is due on the following Lab period.