I-Solubility Product: Acid-Base Volumetric Analysis Dr. Prem D. Sattsangi Copyright © 2009
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- ] = ?
#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
#2 Section-1. Solubility of KHT in presence of a common ion, [K+] Each student will be assigned a concentration of KNO3 from 0.040 M, 0.060, 0.080 M ….to 0.160 M. PROCEDURE: Calculate mass of KNO3 needed to prepare 100 mL of 0.190 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 0.100 L x 101.1 g = 1.92 g 1 L 1 mol H. it I.
#2b-Preparing solution Weigh on the table top balance. [+/- 0.03 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.
#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.
#4 Section-2 Titration in duplicate of the Filtrate Pipet 25.00 mL of filtrate in 2 150 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 0.0412 M ? M ____mL 25.00 mL H. it I.
#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 0.0412 M ? M ____mL 25.00 mL
#6 Section-1. Solubility of KHT in Presence of [K+] added Data: [K+] [KHT] 0.04 0.0436 0.06 0.0382 0.08 0.0362 0.1 0.0313 0.12 0.0252 0.14 0.0205 Graph will be used for U.K. If the solubility of KHT in presence of (U.K.) = 0.0315 M; [K+] added = 0.081 M
#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.