Post on 22-Dec-2015
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+ ionsKsp (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:1. 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
2. 0.190 mol x 0.100 L x 101.1 g = 1.92 g 1 L 1 mol
H. it I.
#2b-Preparing solutionWeigh 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 FILLINGStopper 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 SOLUBILITYNaOH + KHT NaKT + H2O0.0412 M ? M____mL 25.00 mL H. it I.
#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 SOLUBILITYNaOH + KHT NaKT + H2O0.0412 M ? M____mL 25.00 mL
#6 Section-1. Solubility of KHT in Presence of [K+] added
0.03 0.08 0.130.015
0.02
0.025
0.03
0.035
0.04
0.0450000000000001
0.0500000000000001
Solubilty of KHT in presence of [K+]
Series1
Linear (Series1)
[K+] added
So
lub
ilit
y o
f K
HT
[K
HT
]
If the solubility of KHT in presence of (U.K.) = 0.0315 M; [K+] added = 0.081 M
[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
Data:
Graph will be used for U.K.
#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.