Chemistry Class 12 Project (Acetic Acid)

CHEMISTRY PROJECT

SUBMITTED BY: ANAND BABURAJAN ( XII – A )

ESTIMATION OF ACETIC ACID IN DIFFERENT SAMPLES OF VINEGAR

Submitted to Central Board of Secondary Education in partial fulfillment of the requirements for the Senior Secondary Examination

By: Anand Baburajan (XII - A)

DEPARTMENT OF CHEMISTRY BLOOMING BUDS BETHANIA ENGLISH SCHOOL SENIOR SECONDARY

VELLITHURITHY, MARHAMCODE (PO), THRISSUR.

BLOOMING BUDS BETHANIA ENGLISH SCHOOL SENIOR SECONDARY

(AFFILIATED TO CBSE, NEWDELHI, NO: 930307) VELLITHURITHY, MARATHAMCODE, THRISSUR

DEPARTMENT OF CHEMISTRY CERTIFICATE Certified that this is a bonafide record of the project work in CHEMISTRY

Submitted to the Central Board of Secondary Education in partial fulfillment of Senior Secondary Examination.

---------------Faculty Guide

----------------Principal

Submitted for Practical Examination and Viva-Voce held on _ _ _ _ _ _ _ _ _ ---------------------Internal Examiner

------------------------External Examiner

DECLARATION I, ANAND BABURAJAN, hereby declare that this project work entitled “ESTIMATION OF ACETIC ACID IN DIFFERENT SAMPLES OF VINEGAR ” submitted to Blooming Buds Bethania English School Senior Secondary, Velliturithy, Marathamcode, (Affiliated to CBSE, New Delhi, and Affiliation No. 930307) is original record work done by me under the supervision and guidance of Mrs. JEENA J EENA JOSE T., Department of Chemistry. Name of the candidate

Register No

Signature of the candidate

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Countersigned By: Mrs. Jeena Jose T. Teacher in Charge Department of Chemistry Blooming Buds Bethania English School Senior Secondary, Marathamcode.

Place: Marathamcode Date:

ACKNOWLEDGEMENT The success and final outcome of this project required a lot of guidance and assistance from many people and I am extremely fortunate to have got this all along the completions of my project work. Whatever I have done is only due to such guidance and assistance and I would not forget to thank them I have taken efforts in this project. However, it would not have been possible without the kind support and help of many individuals. I would like to extend my sincere thanks to all of them. I am highly indebted to my chemistry teacher Mrs. Jeena Jose T. for her guidance and constant supervision as well as for providing necessary information regarding the project & also for supporting me in completing this project. I also thank our respected Principal Mrs. Remabai V.K and Vice Principal Mrs. Sathidevi Rajagopal for their support. I am thankful to and fortunate enough to get constant encouragement, support and guidance from all teaching staff of Department of Chemistry which helped me in successfully completing this project I would like to express my gratitude towards my parents for their kind co-operation and encouragement which help me in completion of this project.

My thanks and appreciations also go to my colleague in developing the project and people who have willingly helped me out with their abilities.

ESTIMATION OF ACETIC ACID IN DIFFERENT SAMPLES OF VINEGAR

CONTENTS

1. 2. 3. 4.

INTRODUNCTION AIM AI M O F THE TH E P ROJE RO JEC CT THEORY APPA AP PAR R ATUS AT US AND AN D C H EMIC EM ICAL ALS S

5.

PROCEDURE

6.

OBSERVATIONS

7.

CALCULATIONS

8.

CONCLUSION

9.

BIBLIOGRAPHY

INTRODUCTION Acetic acid, also known as ethanoic acid, is an organic chemical compound best recognized for giving vinegar its sour taste and pungent smell. Pure water-free acetic acid (glacial acetic acid) is a colorless hygroscopic liquid and freezes below 16.7°C (62°F) to a colourless crystalline solid. Acetic acid is corrosive, and its vapour is irritating to eyes and nose, although it is a weak acid based on its ability to dissociate in aqueous solutions. Acetic acid is one of the simplest carboxylic acids (the second-simplest, next to formic acid). It is an important chemical reagent and industrial chemical that is used in the production of polyethylene terephthalate terephthalate mainly used in soft drink bottles; cellulose acetate, mainly for photographic film; and polyvinyl acetate for wood glue, as well as many synthetic fibres and fabrics. In households diluted acetic acid is often used in descaling agents. In the food industry acetic acid is used under the food additive code E260 as an acidity regulator. Acetic acid has the empirical formula CH2O and the molecular formula C2H4O2. The latter is often written as CH3-COOH, CH3COOH, or CH3CO2H to better reflect its structure. The ion resulting from loss of H+ from acetic acid is the acetate anion. The name acetate can also refer to a salt containing this anion or an ester of acetic acid.

The crystal structure of acetic acid[4] shows that the molecules pair up into dimers connected by hydrogen bonds. The dimers can also a lso be detected in the vapour at 120 Â°C. They probably also occur in the liquid phase of pure acetic acid, but are rapidly disrupted if any water is present. This dimerisation behaviour is shared by other lower carboxylic acids. Acetic acid can be detected by its characteristic smell. A colour reaction for salts of acetic acid is iron(III) chloride solution, which results in a deeply red colour that disappears after acidification. Acetates when heated with arsenic trioxide form cacodyl oxide, which can be detected by its malodorous vapours. In the form of o f vinegar, acetic acid solutions (typically 5% to 18% acetic acid, with the percentage usually calculated by mass) are used directly as a condiment, and also in the pickling of vegetables and other foodstuffs. Table vinegar tends to be more dilute (5% to 8% acetic acid), while commercial food pickling generally employs more concentrated solutions. The amount of acetic aid used as vinegar on a worldwide scale is not large, but historically, this is by far the oldest and most well-known application.

AIM OF THE PROJECT The aim of the project is to determine volumetrically the amount of acetic acid present in commercial vinegar sample.

THEORY According to the theory of acid base titration, the end point in the titration of vinegar with NaOH will be observed between ph 8 and 10. Therefore in the titration also, the phenolphthalein is a suitable indicator. The reaction between vinegar and NaOH is given by: CH3COOH + NaOH --> CH3COONa + H2O

By knowing the volume of vinegar solution reacting with a definite volume of NaOH solution, the strength of vinegar solution can be calculated. The equation for standardization of NaOH and Oxalic acid is: 2NaOH + (COOH)2 --> 2COONa + 2H2O

APPARATUS AND CHEMICALS 

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Burette and burette stand Pipette (20 ml) Standard flask (100 ml) Conical flash (250 ml) Weighing Bottle Funnel Solution a)0.1 a) 0.1 N NaOH solution prepared by dissolving 4 g NaOH in a litre of pure water. b) Phenolphthalein Phenolphthalein indicator prepared by dissolving 0.4 g phenolphthalein in 500cc of water by constantly stirring (and filtering if needed) Chemicals a)Vinegar a) Vinegar sample b) Oxalic acid (AR)

PROCEDURE 1. PREPARATION OF STANDARD OXALIC ACID SOLUTION

Carefully weigh the dry bottle with about 0.63g of AR oxalic acid crystals in a chemical balance. Determine the weight of the weighing bottle again and find the exact mass of oxalic acid transferred by taking the difference between the two weights. The oxalic acid in the funnel is washed down into the standard flask by a jet of water from a wash bottle (about 20ml). By carefully giving the flask a rotator motion the oxalic acid is dissolved. The funnel and its stem are then rinsed down into the standard flask and the funnel removed. Then make up the solution to the mark and shake well to get uniform concentration. 2. STANDARDISATION OF NaOH SOLUTION

Rinse the burette with a little of oxalic acid solution and then fill it to the zero mark with the acid. Pipette out 20m1 of standard NaOH solution to 250m1 conical flask. Add one or two drops of phenolphthalein phenolphthalein indicator to generate a pink colour to the solution. Titrate this solution against oxalic acid in the burette till the pink colour just disappears. Note the burette reading. Repeat the titration to get concordant titrate values.

3. ESTIMATION OF ACETIC ACID IN VINEGAR

Rinse a clean burette with a small amount of the vinegar sample solution and fill it to the zero mark with the same s ame solution. Now pipette out of 20 ml of NaOH solution into a 250 ml conical flask and add one or two drops of phenolphthalein phenolphthalein indicator. This solution is titrated against the vinegar solution from the burette until the pink colour just disappears. Note Note the burette burette reading. Repeat the titration to get concordant titrated values.

OBSERVATIONS Mass of weighing bottle + oxalic acid crystals = 7.14g Mass of weighing bottle = 6.51g Mass of oxalic acid transferred = 0.63g TABLE 1: OXALIC ACID V/S NAOH SOLUTION - PHENOLPHTHALEIN INDICATOR

S.No.

Volume of NaOH solution

Initial burette reading

Final burette reading

Volume of oxalic acid

1

20ml

0ml

25.2ml

25.2ml

2

20ml

0ml

25.2ml

25.2ml

TABLE 2: VINEGAR SOLUTION (GREEN CHILLIES) V/S NAOH - PHENOLPHTHALEIN PHENOLPHTHALEIN

S.No.




Volume of vinegar solution

1

20ml

0ml

3ml

3ml

2

20ml

0ml

3ml

3ml

TABLE 3: VINEGAR SOLUTION (KALYAN) V/S NAOH - PHENOLPHTHALEIN

S.No.





1

20ml

0ml

3.6ml

3.6ml

2

20ml

0ml

3.6ml

3.6ml

TABLE 4: VINEGAR SOLUTION (KISSAN) V/S NAOH - PHENOLPHTHALEIN

S.No.





1

20ml

0ml

4.5ml

4.5ml

2

20ml

0ml

4.5ml

4.5ml

TABLE 4: VINEGAR SOLUTION (DOUBLE HORSE) V/S NAOH - PHENOLPHTHALEIN

S.No.





1

20ml

0ml

3.5ml

3.5ml

2

20ml

0ml

3.5ml

3.5ml

TABLE 4: VINEGAR SOLUTION (ORMA) V/S NAOH - PHENOLPHTHALEIN

S.No.





1

20ml

0ml

4.2ml

4.2ml

2

20ml

0ml

4.2ml

4.2ml

CALCULATIONS STANDARDISATION OF NaOH SOLUTION

Equivalent mass of oxalic acid=126/2 = 63 Mass of oxalic acid present in 100ml solution =0.63g Normality of oxalic acid, N1 = (0.63*100)/(63*100) = 0.1 N. Volume of NaOH solution, V2= 20ml Volume of oxalic acid required to react with 20ml of NaOH solution, V1= 25.2ml Let the normality of NaOH solution be N2 We know N1 x V1 = N2 x V2 N2 = (N1 x V1)/V2 = (0.1*25.2)/20 = 0.126 N

ESTIMATION OF STRENGTH OF VINEGAR SOLUTION [GREEN CHILLIES]

Normality of NaOH solution, N2 = 0.126 N Volume of NaOH solution, V2 = 20ML Volume of vinegar solution reacting with 20ml NaOH solution, V3 = 3ml

Let normality of vinegar solution be N3, N2 x V2=N3 x V3 N3 = (N2 x V2)/V3 = (0.126 x 20)/3 = 0.84 N Equivalent mass of acetic acid=60 Strength of commercial Vinegar = 5 x N3 x 60 = 5 x 0.84 x 60 = 252 g/l

ESTIMATION OF STRENGTH OF VINEGAR SOLUTION [DOUBLE HORSE]

Volume of vinegar solution reacting with 20ml NaOH solution, V4 = 3.5ml Let normality of vinegar solution be N4, N2 x V2=N4 x V4 N4 = (N2 x V2)/V4 = (0.126 x 20)/3.5 = 0.72 N Equivalent mass of acetic acid=60 Strength of commercial Vinegar = 5 x N4 x 60 = 5 x 0.72 x 60 = 216 g/l

ESTIMATION OF STRENGTH OF VINEGAR SOLUTION [ORMA]


ESTIMATION OF STRENGTH OF VINEGAR SOLUTION [KALYAN]

Volume of vinegar solution reacting with 20ml NaOH solution, V6 = 3.6ml Let normality of vinegar solution be N3, N2 x V2=N6 x V6 N6 = (N2 x V2)/V6 = (0.126 x 20)/3.6 = 0.70 N

Equivalent mass of acetic acid=60 Strength of commercial Vinegar = 5 x N6 x 60 = 5 x 0.70 x 60 = 210 g/l

ESTIMATION OF STRENGTH OF VINEGAR SOLUTION [KISSAN]


CONCLUSION The vinegar with brand name Green Chillies has high normality of 0.84 N and more strength (252 g/l). So among the other brands, Green Chillies is the good quality vinegar.

BIBLIOGRAPHY

BOOKS 1. Comprehensive Practical Chemistry – N.K. Sharma 2. Practical Chemistry – A.O. Thomas 3. NCERT Chemistry Text Book

Chemistry Class 12 Project (Acetic Acid)

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