Chemistry Project on Analysis of Cold Drinks

Comparative Study and Qualitative Analysis of Different Brands of Cold Drinks Available in Market

Aim: Comparative study and qualitative analysis of different brands of cold drinks available in market.

Certificate: It is hereby certified that the original and genuine investigation work has been carried out to investigate about the subject matter and the related data collection and investigation has been completed solely, sincerely and satisfactorily by Rahul of Class XII A, Mother Divine Sr. Sec. Public School (Rohini), regarding his project titled “Content of Cold Drinks Available in the Market”.

Teacher’s Signature:

Acknowledgement: It would be my utmost pleasure to express my sincere thanks to my Chemistry Teachers Mrs. Aditi, Mrs. Richa and Mrs. Shobhna for providing a helping hand in this project. Their valuable guidance, support and supervision all through this project titled “Content of Cold Drinks Available in the Market” are responsible for attaining its present form.

Name: Navi

Class: XII - A

Purpose

In recent days, soft drink brands were put into various questions regarding their purity. News flashed that they contain harmful pesticides, which aroused much interest in knowing their contents because I have been drinking them for years. I wanted to confirm whether the charges imposed on these brands are true or not.

Another fact which inspired me to do this project is that I am in touch with qualitative analysis whose knowledge, with other factors, helped me to do so.

Introduction

The era of cold drinks began in 1952 but the indianization of the industry marked its beginning with the launching of Limca and Goldspot by the Parle group of companies. Since the beginning of cold drinks was highly profitable and luring, many multinational companies launched their brands in India like Pepsi and Coke.

Nowadays, it is observed in general that the majority of people view Sprite, Miranda, and Limca as giving a feeling of lightness, while Pepsi and Thums Up are seen to activate pulse and brain.

Theory

Cold drinks of different brands are composed of alcohol, carbohydrates, carbon dioxide, phosphate ions, etc. These soft drinks give a feeling of warmth and lightness and have a tangy taste which is liked by everyone. Carbon dioxide is responsible for the formation of froth on shaking the bottle.

The carbon dioxide gas is dissolved in water to form carbonic acid, which is also responsible for the tangy taste. Carbohydrates are naturally occurring organic compounds and are a major source of energy to our body. The general formula of carbohydrates is C_x(H_2O)_y.

On the basis of their molecule size, carbohydrates are classified as:

• Monosaccharides
• Disaccharides
• Polysaccharides

Glucose is a monosaccharide with formula C6H12O6. It occurs in the free state in ripe grapes and in many sweet fruits. It is also present in human blood to the extent of about 0.1%.

Sucrose is one of the most useful disaccharides in our daily life. It is widely distributed in nature in juices, seeds and flowers of many plants. The main source of sucrose is sugar cane juice which contains 15-20% sucrose, and sugar beet which has about 10-17% sucrose. The molecular formula of sucrose is C12H22O11. It is non-reducing in nature, whereas glucose is reducing.

Cold drinks are slightly acidic in nature and their acidity can be measured by finding their pH value. The pH values also depend upon the acidic contents such as citric acid and phosphoric acid.

Apparatus

• Test tube
• Test tube holder
• Test tube stand
• Stopwatch
• Beaker
• Burner
• pH paper
• Tripod stand
• China dish
• Wire gauge
• Water bath

Chemicals Required

• Iodine solution
• Potassium iodide
• Sodium hydroxide
• Fehling’s A & B solution
• Lime water
• Concentrated HNO3
• Benedict’s solution
• Ammonium molybdate

Detection of pH

1-2 drops of the sample of cold drink of each brand were taken and placed on pH paper. The change in colour of the pH paper was noted and compared with the standard pH scale.

Observation

Serial No.	Name of Drink	Colour Change	pH Value
1	Coca Cola	Pink	1-2
2	Sprite	Orange	3
3	Limca	Pinkish	3-4
4	Fanta	Light pink	2-3

Inference

Soft drinks are generally acidic because of the presence of citric acid and phosphoric acid. pH values of cold drinks of different brands differ due to variation in the amount of acidic contents.

Test for Carbon Dioxide

Experiment

As soon as the bottles were opened, the sample from each was passed one by one through lime water. The lime water turned milky.

Observation

Sr. No.	Name of the Drink	Time Taken (sec.)	Conclusion
1	Coca Cola	26.5	CO2 is present
2	Sprite	21	CO2 is present
3	Limca	35	CO2 is present
4	Fanta	36	CO2 is present

Inference

All the soft drinks contain dissolved carbon dioxide in water. The carbon dioxide (CO2) dissolves in water to form carbonic acid, which is responsible for its tangy taste.

Chemical Reaction Involved

Ca(OH)2 (s) + CO2 (g) → CaCO3 (s) + H2O (l)

Test for Glucose

Glucose is a reducing sugar. Its presence is detected by the following tests:

1. Benedict’s Solution Test

A small sample of cold drink of each brand was taken in a test tube and a few drops of Benedict’s reagent were added. The test tube was heated for a few seconds. Formation of reddish colour confirms the presence of glucose in cold drinks.

Observation

Sr. No.	Name of the Drink	Observation	Conclusion
1	Coca Cola	Reddish colour	Glucose present
2	Sprite	Reddish colour	Glucose present
3	Limca	Reddish colour	Glucose present
4	Fanta	Reddish colour	Glucose present

Inference

All the samples gave a positive test for glucose with Benedict’s reagent. Hence all the drinks contain glucose.

2. Fehling’s Solution Test

A small sample of cold drink of each brand was taken in a test tube and a few drops each of Fehling’s A solution and Fehling’s B solution were added in equal amounts. The test tube was heated in a water bath for 10 minutes. Appearance of a reddish-brown precipitate confirms the presence of glucose in cold drinks.

Observation

Sr. No.	Name of the Drink	Observation	Conclusion
1	Coca Cola	Reddish brown precipitate	Glucose present
2	Sprite	Reddish brown precipitate	Glucose present
3	Limca	Reddish brown precipitate	Glucose present
4	Fanta	Reddish brown precipitate	Glucose present

Inference

All the samples gave a positive test for glucose with Fehling’s solutions (A & B). Hence all the cold drinks contain glucose.

Test for Phosphate

A sample of each brand of cold drink was taken in a separate test tube and ammonium molybdate followed by concentrated nitric acid (HNO3) was added to it. The solution was then heated and the colour of the precipitate confirms the presence of phosphate ions.

Observation

Sr. No.	Name of the Drink	Observation	Conclusion
1	Coca Cola	Canary-yellow precipitate	Phosphate is present
2	Sprite	Canary-yellow precipitate	Phosphate is present
3	Limca	Canary-yellow precipitate	Phosphate is present
4	Fanta	Canary-yellow precipitate	Phosphate is present

Inference

All the soft drinks contain phosphate ions, detected by the formation of a canary-yellow precipitate.

Chemical Reaction Involved

NaHPO4 + 12(NH4)2MoO4 + 21HNO3 + 3H+ → (NH4)3PO4.12MoO3 + 21NH4NO3 + 12H2O

Test for Alcohol

Samples of each brand of cold drink were taken in separate test tubes and iodine followed by potassium iodide and sodium hydroxide (NaOH) solution was added to each test tube. The test tubes were then heated in a hot water bath for 30 minutes. A yellow-coloured precipitate confirms the presence of alcohol in cold drinks.

Observation

Sr. No.	Name of the Drink	Observation	Conclusion
1	Coca Cola	Yellow precipitate	Alcohol is present
2	Sprite	Yellow precipitate	Alcohol is present
3	Limca	Yellow precipitate	Alcohol is present
4	Fanta	Yellow precipitate	Alcohol is present

Inference

All brands of cold drinks contain alcohol.

Chemical Reaction Involved

CH3CH2OH + 4I2 + 6NaOH → CHI3 + HCOONa + 5NaI + 5H2O

Test for Sucrose

5 ml samples of each brand of cold drink were taken in a china dish and heated very strongly until a change occurred. A black-coloured residue confirms the presence of sucrose in cold drinks.

Observation

Sr. No.	Name of the Drink	Observation	Conclusion
1	Coca Cola	Black residue	Sucrose is present
2	Sprite	Black residue	Sucrose is present
3	Limca	Black residue	Sucrose is present
4	Fanta	Black residue	Sucrose is present

Inference

All the brands of cold drinks contain sucrose. However, the amount of sucrose varies in each brand. Fanta contained the highest amount of sucrose.

Result

After conducting several tests, it was concluded that the different brands of cold drinks - Coca Cola, Sprite, Limca, and Fanta - all contain glucose, alcohol, sucrose, phosphate ions, and carbon dioxide. All are acidic in nature.

On comparing the pH values of different brands, Coca Cola is the most acidic and Limca is the least acidic of the four brands tested.

The pH value of Coca Cola is nearly equal to that of a disinfectant, which is harmful to the body.

Among the four samples of cold drinks taken, Sprite has the maximum amount of dissolved carbon dioxide and Fanta has the minimum amount of dissolved carbon dioxide.

Conclusion

Disadvantages of Cold Drinks

1. Soft drinks are more harmful than plain sugar solution, as they contain sugar in large amounts which can cause diabetes.
2. Soft drinks can cause weight gain as they interfere with the body’s natural ability to suppress hunger.
3. Soft drinks have the ability to dissolve calcium, so they are harmful to bones.
4. Soft drinks contain phosphoric acid which has a pH of 2.8 and can dissolve a nail in about 4 days.
5. For transportation of soft drink syrup, commercial trucks must use the hazardous material placards reserved for highly corrosive material.
6. Soft drinks have the ability to remove blood stains, indicating they are chemically aggressive.

Uses of Cold Drinks

1. Cold drinks can be used as toilet cleaners.
2. They can remove rust spots from chrome car bumpers.
3. They clean corrosion from car battery terminals.
4. Soft drinks are used as an effective detergent to remove grease from clothes.
5. They can loosen a rusted bolt.

Bibliography

Laboratory Manual of Chemistry - Veena Suri

Dinesh Companion Chemistry - S.K. Malhotra

Websites:

• www.googlearth.com
• www.cseindia.org

Teacher’s Remarks: