Extraction of Indicators from Beetroot and Onion CBSE Project

Extraction of Indicators from

Beetroot and Onion

By: Fuzel Salim 1

XII-B

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CONTENTS No Page No 1 3 2 5 3 7 4 9 5 11 6 13 7 15 8 17 9 19

Subject Contents Certificate

Acknowledgement pH Indicator Beetroot Beetroot as an Indicator Preparation of the Indicator Detection of pH Range Onion 3

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Onion as an Indicator Olfactory Indicators

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Certificate This is to certify that Fuzel Salim of class XII-B has completed this project under my supervision for the academic year 20152016. ……………… …. 5

(Internal Examiner) Seal: Date: ……………… ….. (External Examiner)

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Acknowledge ment I wish to express my sincere gratitude to Dr. Alim Khan for providing me an opportunity to do my project work on “Extraction of Indicators from Onions and Beetroot”. This project bears an imprint of 7

many people. I sincerely thank my project partner for guidance and encouragement in carrying out his project work and cooperating with me. I thank my brother for his kind co-operation to the completion of my project work. Last but not the least I wish to express a sense of gratitude and love to my beloved parents for their help, manual support and strength.

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pH Indicator

A pH indicator is a halochromic chemical compound added in small amounts to a solution so the pH (acidity or basicity) of the solution can be determined visually. Hence, a pH indicator is a 9

chemical detector for hydronium ions (H3O+) or hydrogen ions (H+) in the Arrhenius model. Normally, the indicator causes the color of the solution to change depending on the pH. Indicators can also show change in other physical properties; for example, olfactory indicators show change in their odor.

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Beetroot 11

The beetroot is the taproot portion of the beet plant, usually known in North America as the beet, also table beet, garden beet, or red or golden beet. It is several of the cultivated varieties of Beta vulgaris grown for their edible taproots and their greens. These varieties have been classified as B. vulgaris subsp. vulgaris Conditiva Group. Other than as a food, beets have use as a food coloring and as a medicinal plant. Many beet products are made from other Beta vulgaris varieties, particularly sugar beet.

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Beetroot as an Indicator 13

Beetroot Red, is a glycosidic food dye obtained by hydrolyzing the glucose molecule, Betanin. The colour of Betanin depends on pH. It is bright bluish-red, becoming blue-violet as the pH increases. Once the pH reaches alkaline levels Betanin degrades by hydrolysis, resulting in a yellow-brown colour.

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Preparation of the Indicator 1). 300.0 g of chopped Beetroot was added to 50.00cm3 of boiling water in a beaker and was boiled continuously for 45 minutes. 2). After allowing the beaker to cool for 15 minutes, boiled Beetroot were squashed and the liquid was filtered. 3). The residues were squeezed once again and the liquid was evaporated to get a highly concentrated portion of the indicator. 16

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Detection of pH Range •A

series of solutions in the range pH 1.0-13.0 was prepared by using 1.0 M NaOH and 1.0 M HCl acid.

• When the indicator was added to the

prepared series of solutions the colour was changed from red to yellow in between pH 10.0-12.0.

• In

order to get the exact pH range, another series of solutions was prepared by diluting the pH 10-12 solution range into 10.10, 10.20, ……,12.00 and 0.05 ml of the indicator was added to each solution.

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• A colour change was observed in the pH range 10.80-11.20, which is the working pH range of Beetroot.

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Onion

The onion (Allium cepa L.) (Latin cepa = onion), also known as the bulb onion or 20

common onion, is a vegetable and is the most widely cultivated species of the genus Allium. This genus also contains several other species variously referred to as onions and cultivated for food, such as the Japanese bunching onion (A. fistulosum), the Egyptian onion (A. ×proliferum), and the Canada onion (A. canadense). The name "wild onion" is applied to a number of Allium species, but A. cepa is exclusively known from cultivation and its ancestral wild original form is not known, although escapes from cultivation have become established in some regions. The onion is most frequently a biennial or a perennial plant, but is usually treated as an annual and harvested in its first growing season.

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Onion as an Indicator Onion is an olfactory indicator. They have a characteristic odour but when chopped onions are kept in a dilute solution of sodium hydroxide, they lose their characteristic odour. However, on keeping the chopped onions in a dilute acidic solution, the characteristic odour of onions is not lost. This experiment can help in identifying acidic or alkaline solution. Red onion can act as a visual indicator at the same time. It changes from pale red in acid solution to green in basic solution.

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Clove Oil Extract

Vanilla

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Onions

Olfactory

Indicators

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An Olfactory indicator is a substance whose smell varies depending on whether it is mixed with an acidic or basic solution. Olfactory indicators can be used in the laboratory to test whether a solution is a base or an acid, a process called olfactory titration. Onion , clove oil and vanilla extract are examples. They lose their smell with bases but not with acids. Olfactory indicators can be used to engage visually impaired students in laboratory work.

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