Chem 112

investigate 2 Acetic Acid Content of Vinegar By Kelsey Huber Chem 112L-01-George Gachumi September 19, 2011 Lab partners Danielle Antes, Alex Ogren, Vanessa Kellems In this experiment acetic acid will be titrated with atomic number 11 hydroxide. As the sodium hydroxide is titrated into the acetic acid it is measured by pH. The sodium hydroxide is added into the acetic issue in small increments using a burette. The concentration of acetic acid honests at 0. 91. 5M and the known value of the acetic acid is 0. 833M.The percent fault of the experiment averages at 0. 66%. Possible errors could include incorrect measurements of sodium hydroxide and/or acetic acid. Background Titration is when one solution is slowly added to some other solution so that the reaction between the two burn down be accurately recorded or measured. For example, when a base is slowly added to an acid the equality point should be neutral. Methods of titration are even apply in the food industry to express t he oil and fat contents in different products.For example, titration is used in the cheese and the wine business to test if the product is ready for consumption. Procedure Hirko, R. Chemistry 112L General Chemistry I Laboratory, 5th ed. bluedoor Eden Prairie, MN, 2011 Experiment 2. Results chart A. 1 shows the second derivative used to find the volume of NaOH to equivalence point which equals 8. 02 ml. Graph A. 2 shows the titration curve of the pH versus the volume of the solution. Graph A. 1 Graph A. 2Discussion The titration of sodium hydroxide to acetic acid eventually produced a dark pink solution. The equivalence point of this solution is a flea-bitten acid. The acetic acid molarity of commercial vinegar varied slightly in the three trials. In trial one the vinegar molarity was 0. 173 M, in trial two it was 1. 061 M, and in trial three it was 1. 322 M. The concentration of acetic acid was calculated at 0. 91. 5 M, by taking the average of three trials. This is within 0. 067 M of the known value which is 0. 833 M.By inspection of the titration curves there could be a difference based on the exact amount of sodium hydroxide being dropped from the burette into the acetic acid solution. At the equivalence point the pH is non seven because acetic acid is a washed-out acid and it is being mixed with a strong base, sodium hydroxide. The indicator turned red when it reached the equivalence point. Phenolphthalein was a good indicator for the titration of a powerless acid with a strong base because it was the solution that caused the red pretext as the sodium hydroxide and acetic acid reached an equivalence point.Phenolphthalein would however not be a good indicator for titration of a weak base with a strong acid because the phenolphthalein reacted with the sodium hydroxide to create the red color it was not turning red as a result of the acetic acid. Inaccuracies in the determined concentration of sodium hydroxide to acetic acid can be attributed to possib le measurement errors. Inaccurate measurements while adding the sodium hydroxide from the burette into the acetic acid throughout the three trials could result in unhomogeneous outcomes on the graphs effecting results such as the equivalence point and the titration curve.