Lab how much acetic acid is in vinegar

As sodium hydroxide, NaOH, is incrementally added to the acid solution, some of the hydrogen ions will be neutralized. As the hydrogen ion concentration decreases, the pH of the solution will gradually increase. The volume of based required to completely neutralized the acid is determine at the equivalence point of titration. Figure Acid-base titration curve of weak acid titrated with NaOH. In this experiment, titration of vinegar sample with a standardized sodium hydroxide solution will be done.

To standardize the sodium hydroxide solution, of a primary standard acid solution is initially prepared. In general, primary standard solutions are produce by dissolving a weighed quantity of pure acid or base in a known volume of solution. Sodium carbonate, Na2CO3, is the most commonly used based. Most acids and bases e. To standardize one of these acid or based solutions, titration of the solution with a primary standard should be done. Sample calculation for standardizing a based with KHP Figure 3 depicts the titration curve of 1.

Determine the molarity of the NaOH solution. The volume of NaOH used at the equivalence point is Assume the density of the vinegar solution is 1. Sample calculations for determining the acetic acid concentration in vinegar by titration with standard base A The calculation has been recorded. A mL beaker is weighed and the mass was recorded to the nearest 0. The mass of the beaker and KHP was recorded to the nearest 0. The mass of KHP by difference was calculated and the data was recorded.

Steps 1 to 3 was repeated to perform a second trial to standardized the NaOH solution. The graph of pH versus NaOH was plotted. The molarity of sodium hydroxide has been calculated for titration 1 and 2. The average molarity of sodium hydroxide solution for titration 1 and 2 was calculated. The resulting sodium hydroxide concentration will be used in Part B of the experiment. Part B: Molarity of acetic acid and percent of vinegar.

A sufficient water, 75 to mL were added to cover the pH electrode tip during the titration. It is therefore possible to determine the concentration of acetic acid in vinegar by titrating the vinegar with a strong base such as aqueous sodium hydroxide solution. Please do not block ads on this website. When a weak acid such as acetic acid is titrated with a strong base such as aqueous sodium hydroxide solution, the pH at the equivalence point will be greater than 7. Suitable indicators for this experiment are phenolphthalein or thymol blue.

Rinse a clean Pipette If we have helped you, please help us fix his smile with your old essays Purpose In this lab we will observe the products of decomposition of potassium perchlorate KClO4. Tutor and Freelance Writer.

Science Teacher and Lover of Essays. Article last reviewed: St. Skip to content. Titration of Vinegar Lab Answers. Introduction Vinegar is a common household item containing acetic acid as well as some other chemicals. Fear and Destiny in Oedipus Rex: Analysis. Find out More. In order to know when the equivalence point is reached, an indicator solution called phenolphthalein is added to the vinegar at the beginning of the titration.

Phenolphthalein is a pH sensitive organic dye. Phenolphthalein is colorless in acidic solutions like vinegar, and deep pink in basic solutions like sodium hydroxide. Using this data, the molarity and mass percent of acetic acid in vinegar can be determined by performing a series of solution stoichiometry calculations see Calculations Section. If any NaOH spills on you, rinse immediately under running water for up to 15 minutes and report the accident to your instructor.

Your instructor will demonstrate the correct use of the volumetric pipette and burette at the beginning of the lab session.

Detailed instructions on how to use a pipette are also found on the last page of this handout. Note that three titrations must be performed. Color at equivalence point — to be recorded by your instructor. Write the balanced equation for the neutralization reaction between aqueous sodium hydroxide and acetic acid.

Use your two best sets of results with the palest pink equivalence points along with the balanced equation to determine the molarity of acetic acid in vinegar. Show all work for each step in the spaces provided. Use your two best sets of results along with calculated values in the previous table to determine the mass percent of acetic acid in vinegar. Titration Procedure Your instructor will demonstrate the correct use of the volumetric pipette and burette at the beginning of the lab session.

Obtain a mL burette, 5-mL volumetric pipette and a pipette bulb from the stockroom. Allow the distilled water to drain out through the tip in order to ensure that the tip is also rinsed. Use a funnel to do this carefully, below eye-level, and preferably over the sink. After this you will need to flush the tip of the burette — your instructor will show you how to do this. Also record the exact molarity of the NaOH aq , which is labeled on the stock bottle.

Preparing the vinegar sample The volumetric pipette used in this lab is designed to measure and transfer exactly 5. First, rinse the inside of the volumetric pipette with distilled water. Using the pipette bulb, draw the water into the pipette up above the 5-mL mark, then allow it to drain out through the tip.