Question

how would you calculate the expected pH for solution 7, 8, 9, 10, and 11? (I am confused on how you calculate the dilutions for finding the expected pH too)

Ka= 1.4x10^-5

pKa= 4.85

Part B - The Effect of Adding Acid or Base to a Buffered Solution Solution 6 16. Prepare a buffer solution by mixing 30.0 mL of 0.10 M HOAc and 40.0 mL of 0.10 M NaOAc. Measure the pH of the resulting solution with the pH meter and record it in your lab notebook. 17. Add three drops of Universal Indicator to the solution. Record the color and estimated pH in your lab notebook Solution 7 Ka .4X10 Ka-4.85 18. Divide the Solution 6 into three 20 mL aliquots. To the first aliquot, add 2.0 mL of 0.10 M HCl. Measure the pH of the resulting solution using the pH meter and record it in your lab notebook. Record the color and estimated pH. Solution 8 19. To the second aliquot of Solution 6, add 2.0 mL of 0.10 M NaOH. Measure the pH of the resulting solution using the pH meter and record it in your lab notebook. Record the color and estimated pH. Solution 9 20. Dilute the third aliquot of Solution 6 with an equal volume of deionized water (should be approximately 20 mL; adjust the volume of water as necessary). Measure the pH of the resulting solution using the pH meter and record it in your lab notebook. Record the color and estimated pH. Solution 10 21. Place 20.0 mL of deionized water into a beaker. Add three drops of Universal Indicator to the solution. Record the color and estimated pH in your lab notebook. 22. Add 2.0 mL of 0.10 M HCl to the beaker and swirl gently to mix. Measure the pH of the resulting solution using the pH meter and record it in your lab notebook. Record the color and estimated pH. Solution 11 23. Place 20.0 mL of deionized water into a beaker and add three drops of Universal Indicator 24. Add 2.0 mL of 0.10 M NaOH to the beaker and swirl gently to mix. Measure the pH of the resulting solution using the pH meter and record it in your lab notebook. Record the color and estimated pH. Data Analysis For each of the six solutions, calculate the expected pH based on how the solution was prepared, again allowing for any dilution taking place. For Solutions 7 and 8, make sure to take into account the acid-base reaction that occurs when an acid or base is added to the buffer. Compare the calculated and measured pH values for each solution.

Answer 1

Nav A solution 72 30.0 one of o. im Hotet 4o.ome of o.lom millmoles of Hotca 30.080.10 = 3.0mmol, millimoles + Necesta a 4000 l0 = 4.omme, on addition of 2roml of olomice sa. 200 x 0:10= 0.20 mmol, mmole of HoAc = 13.0+ 0,20= 1.2 mmol. mmole of NGOAC = Tor 0.20 - mad, 1-133 Pa ka loo (Neofc) a 4.8st lag 1.133 4.825 | 0 [o] Solutin 8: mmole of Nally added a foox 0110 eco2 mmol. mm, 4 kbc = (2x - 3) = 80 mm). mer of Anette 14.0 +0.2) = 1.533 mmal, přs 4.85 + hogy legyen) - 3.133 Solution 9: On dilution number of millimales of norte and - Neute will remains same and ph will be same as that of solenton 6. p=4085+ log ( 13 ) = 4.975 Suluhan 10 : MV, amave 2.0 mxolom = mx 22.ome _ M 0.009091 merte? 900) = 2.041 = 0.009091m Solution to Sometten a goome xorom (NaOH) = 2200 me 191) = 2.00ny Plz 14- 2.0414 = 11-959