LAB#7

LAB REPORT 6. Then, place the tip of the buret with the base titrant just inside the beaker, with the tip below the rim. 7. Titrate the acid by adding the base from the buret in 2-4-mL increments, stirring continuously and, noting the pH after each addition. (Note: When a weak base is involved, use your discretion on the volume of titrant to be added… sometimes 6-8 mL increments may be necessary) 8. When successive pH readings begin to increase rapidly, add the titrant in smaller 9. increments (1 mL or in drops) until successive pH readings are increasing only slightly. Gradually increase the amount of base added (not to exceed 2 mL at a time), until the pH reaches about pH = 10 (or over), or when the letter “S” is formed by the points. 10. Prepare a titration curve by plotting the volume of base added as the abscissa and the corresponding pH as the ordinate. Determine the equivalence point for each titration. Data & Result NH4OH with CH 3 COOH (Identify specific samples used) Trial mL Base pH Trial mL Base pH Trial mL Base pH 1 0.00 2.76 12 16.50 4.62 23 33.00 8.17 2 1.50 3.22 13 18.00 4.70 24 34.50 8.45 3 3.00 3.55 14 19.50 4.78 25 36.00 8.63 4 4.50 3.77 15 21.00 4.85 26 37.50 8.76 5 6.00 3.91 16 22.50 4.95 27 39.00 8.86 6 7.50 4.03 17 24.00 5.05 28 40.50 8.94 7 9.00 4.16 18 25.50 5.18 29 42.00 9.00 8 10.50 4.26 19 27.00 5.34 30 43.50 9.06 9 12.00 4.34 20 28.50 5.56 31 45.00 9.12 10 13.50 4.45 21 30.00 5.94 32 46.50 9.16 11 15.00 4.51 22 31.50 7.45 33 48.00 9.2 THANH TIN LAM 2