LEARN MORE...

Acetic Acid in Vinegar Lab Report

Content type

User Generated

Subject

Chemistry

Type

Lab Report

Uploaded By

zecyntzna

Pages

Showing Page:

1/9

Experiment 4: Analysis of Acetic Acid in Vinegar

INTRODUCTION

Titration is a method of analysis where a solution of known concentration (standard

solution) is used to determine the concentration of an unknown solution. The known solution

(titrant) is added to a known quantity of the analyte using a buret until the reaction is complete.

The change in color of the added indicator or the change in color of the solution indicates the end

of the reaction, known as the endpoint [1].

Before titration, standardization must be done first. Standardization is the process of

determining the exact concentration of a solution. A standard solution can be prepared by

dissolving a known amount of primary standard, a pure and stable compound with high molecular

weight, in a known volume of liquid [2].

This experiment aims to standardize a solution of NaOH by using a primary standard,

potassium hydrogen phthalate (KPH) and to determine the percentage acidity of a commercial

vinegar.

METHODOLOGY

A. Preparation of 0.10M NaOH solution

To prepare the NaOH solution, approximately 4 grams of NaOH pellets were

weighed using the top loading balance. After weighing, the pellets were then dissolved in

50 mL of water in a 250-mL beaker. After the pellets were all dissolved, the solution was

transferred to the 1-liter volumetric flask. Distilled water was continuously added until the

1-liter mark was reached.

B. Standardization of 0.10M NaOH

Using the analytical balance, 3 samples of KHP with masses between 0.4000 to

0.6000 grams were weighed separately. Two of the samples were each placed in an

Erlenmeyer flask and one was placed in a Florence flask. Each of the sample was dissolved

Showing Page:

2/9

by adding 100 mL of distilled water into the flasks. After dissolving, 5 drops of

phenolphthalein indicator was added into the solution.

For titration of the KHP sample, the 50-mL buret was clamped to the iron stand and

was filled with NaOH solution up to the 50 mL mark of the burette. The KHP sample was

titrated with the NaOH solution. The intial and finals readings of the NaOH solution in the

buret were recorded. These steps were repeated for the next two KHP samples. The

molarity of the NaOH solution from each trial was calculated.

C. Determination of Acetic Acid in Vinegar

Three flasks were weighed separately using the analytical balance. Five milliliters

of commercial vinegar were added to each flask. The flasks were weighed again to

determine the weight of the vinegar added. Fifty milliliters of distilled water and 3 drops

of phenolphthalein indicator were added into each of the flask. Each of the vinegar sample

was titrated using the standardized NaOH solution. The flasks were constantly swirled until

the sample became very light pink. The initial and final readings of the NaOH solution in

the buret were recorded. The percent acidity of the vinegar was computed.

RESULTS AND DISCUSSION

Table 1: Data for NaOH Standardization

Trial 1

Trial 2

Trial 3

Weight of KHP

0.4965 g

0.554 g

0.5711 g

Showing Page:

3/9

End of Preview - Want to read all 9 pages?

Access Now

Unformatted Attachment Preview

Experiment 4: Analysis of Acetic Acid in Vinegar INTRODUCTION Titration is a method of analysis where a solution of known concentration (standard solution) is used to determine the concentration of an unknown solution. The known solution (titrant) is added to a known quantity of the analyte using a buret until the reaction is complete. The change in color of the added indicator or the change in color of the solution indicates the end of the reaction, known as the endpoint [1]. Before titration, standardization must be done first. Standardization is the process of determining the exact concentration of a solution. A standard solution can be prepared by dissolving a known amount of primary standard, a pure and stable compound with high molecular weight, in a known volume of liquid [2]. This experiment aims to standardize a solution of NaOH by using a primary standard, potassium hydrogen phthalate (KPH) and to determine the percentage acidity of a commercial vinegar. METHODOLOGY A. Preparation of 0.10M NaOH solution To prepare the NaOH solution, approximately 4 grams of NaOH pellets were weighed using the top loading balance. After weighing, the pellets were then dissolved in 50 mL of water in a 250-mL beaker. After the pellets were all dissolved, the solution was transferred to the 1-liter volumetric flask. Distilled water was continuously added until the 1-liter mark was reached. B. Standardization of 0.10M NaOH Using the analytical balance, 3 samples of KHP with masses betw ...
Purchase document to see full attachment

Tags: acetic acid Vinegar Acetic Acid In Vinegar titration standardization