Objective- Determine the Acetic acid level contained within the vinegar sample
Background- Per the FDA regulation which states that consumer vinegar may contain no less than four percent and no more than five percent Acetic Acid, we will determine the Acetic Acid content of a sample of the vinegar in question through titration. After standardization of our titrant, which in this case will be NaOH, we will use this along with the indicator Phenolphthalein, to titrate the vinegar to determine the concentration of Acetic Acid in the sample.
Equipment and reagents- We will use a 50mL beaker, a graduated buret, spatula, droplet applicator, 125mL Erlenmeyer flask, hot plate, and a container of snow. The reagents we will use are KHP, NaOH, distilled water, Vinegar sample and Phenolphthalein.
Procedure- (Refer to the attached procedure contained in, Vinegar, an FDA Investigation)
Data-
Titration of KHP | Trial 1 | Trial 2 | Trial 3 | Mass of KHP | 0.1 g | 0.1 g | 0.1 g | Moles of KHP | 4.9E-4 | 4.9E-4 | 4.9E-4 | Moles of NaOH | 4.9E-4 | 4.9E-4 | 4.9E-4 | Initial Volume of NaOH | 0.00 | 0.00 | 0.00 | Final Volume of NaOH | 4.7 mL | 5.0 mL | 5.0 mL | Total Volume of NaOH | 4.7 mL | 5.0 mL | 5.0 mL | Molarity of NaOH | 10.4E-5 | 9.8E-5 | 9.8E-5 | Average Molarity of NaOH | 1.0E-4 |
Titration of Vinegar | Trial 1 | Trial 2 | Trial 3 | Volume of Vinegar | 1.0 mL | 1.0 mL | 1.0 mL | Mass of Vinegar | 1.004 g | 1.004 g | 1.004 g | Initial Volume of NaOH | 0.00 | 0.00 | 0.00 | Final Volume of NaOH | 8.8 mL | 8.5 mL | 8.2 mL | Total Volume of NaOH | 8.8 mL | 8.5 mL | 8.2 mL | Moles of NaOH | 8.8E-4 | 8.5E-4 | 8.2E-4 | Moles of Acetic Acid | 8.8E-4 | 8.5E-4 | 8.2E-4 | Mass of Acetic Acid | 5.28E-2 g | 5.10E-2 g | 4.91E-2 | Percent of Acetic Acid | 5.26% | 5.08% | 4.91% | Average Percent Weight of Acetic Acid in Vinegar Sample | 5.08% |
Calculations-
Titration of KHP