Question

EXP. 5 BUFFERS, TITRATION CURVES, AND INDICATORS STUDENT COPY DATA SHEET RECORD YOUR DATA HERE AS YOU DO THE EXPERIMENT You must record measurements to the correct number of decimal places, and with the appropriate units, for each piece of equipment used. Name of Partner: Not applicable Concentration of stock NaOH (from Exp. 3 Brown Bottle): 0.1135 M Part 1 - Titration Curves Make sure all pH readings have the appropriate number of decimal points pH of acetic acid: 3.29 (initial pH reading) pH Volume of Titrant (mL) pH pH Volume of Titrant (mL) 0.00 PH Volume of Titrant (mL) 22.97 Volume of Titrant (mL) 3.29 16.21 7.53 11.64 11.71 2.123.87 | 16.29 8.70 23.99 4.09 16.31 9.11 6.04 16.39 9.53 4.24 4.52 4.73 4.98 8.03 16.49 9.90 10.24 16.51 9.99 12.02 5.24 16.61 10.17 13.02 5,39 16.78 10.44 14.01 5.59 17.01 10.62 15.04 17.50 10.91 15.49 18.08 11.01 5.81 6.09 6.55 7.00 15.92 19.02 11.12 16.12 20.89 11.40

Answer 1

8.2 ---- Equivalence point Buffer region 4 76 "Half-equivalencei "point 18.15 mL 16.3 mL 8 12 16 20 Volume of NaOH (mL) 0 4 24

CH₂COOH + Naah - Chacer Nathon at half ernivalence point, [CH₂ Cent] 2 [edy cos Na] 2 Henderson- Hasselbalch equation te PH= pka + log [Cl? CeoNa] photo sorm [Chocooth and at half errívaline point .PH = pha thoa [ctacooNa PH 2 Pka tlog! Tchetrona] pH = pka. for Titration, 01135M Naot used on from the plot of pH vs. volume of Naots. at esnivalince point, vohamed Naat resnined = 16.3 m2 eind Correspondir PH = 8.2 r. at half ernivaline point, volumed Nach: 8.15 mL and corresponding PH=4.76. i pkast acid 4.76 prac 4.76 - logka=4,76 Montoro road scorer ka= 10 4.76 1.7378x105 initial pH of acetic and = 3.29 : PH - 3.29 - log [t t] = 3.29 [H+] = 10 3.29 = 5:129x104m.

It encool 2 CH₂ Could CH Con +44 a-si 129x104 5012980 5.129x104 as initial ko [etty coo] [144] Caneintram kas Lly coold] 1.738x105 - (5. 129x104) a-5. 129x104 1.798810*a - 8.913x10-9 - 2631X10 1.7380105 a = 2.631X107 + 8.9138109 1.738810a - 2.71988107 a 2.71988107 1.7180105 -0.0157M. concentraction of unknown netic and = 0.0157M #Note: For Calculation of unknown as neid Concentration uring equivalence point volume from graph. Then initione volume at neid should be given which volume used in titration . Vacid & Carid = V Base & Bene CAcid - Bare X Chare Vacid Canid = 16.3 x 0.1135 Vacid