EXPERIMENT 1PART 2

APPLICATION: MAKING PH INDICATOR

ABSTRACT This experiment objective are to learn how to make pH meter and to learn

how to prepare buffer system. Acidity is measured on a pH scale. pH stands for "potential for Hydrogen." Acidity is caused by hydrogen atoms that have lost their electrons and are roaming free in water [H+]. The opposite of acidic is alkaline (or basic). Alkaline gets its name from the "al kali" plant whose ashes are capable of neutralizing acids. It does this because it contains KOH. The "OH" is called hydroxide and as the equation shows, it combines with the acid [H+] to form water. Extract from part of plant that have most pigmented. Then, after filtration take place, extract of plant is used to test the pH range of the indicator. The solution that have range 1 until 13 are prepared to test the extract of red cabbage, turmeric, soap, detergent, vinegar and orange juice. The pigment in red cabbage is known for its ability to change colors depending on the pH (level of acidity) that it comes in contact with compared to turmeric. Vinegar, orange juice. And others is needed to check how the red cabbage and turmeric extract responds to an acid. and based.

INTRODUCTION

Acidity or alkalinity is measured by chemists in term of the concentration of the hydrogen ion. Thus pH (literally potential of Hydrogen) is a symbol representing quantitatively the hydrogen ion concentration. Thus pure water at normal temperature has a value of 7. pH values from 0 to 7 indicate a decreasing sequence of acidity, pH values from 7 to 13 an increasing sequence of alkalinity.

Red cabbage contains a pigment molecule called flavin (an anthocyanin). This water-soluble pigment is also found in apple skin, plums, poppies, cornflowers, and grapes. Very acidic solutions will turn anthocyanin a red color. Natural solutions result in a purplish color. Basic solutions appear in greenish-yellow. Therefore, it is possible to determine the pH of a solution based on the color it turns the anthocyanin pigments in red cabbage juice. Turmeric(Curcuma longa)is a plant whose parts are often used as a spice in cooking. Turmeric is an example of a natural pH indicator which means that it can be used to determine a substance’s pH.

 

MATERIAL AND METHOD 1. EXTRACTING THE INDICATOR

RED CABBAGE TURMERIC

macerate macerate

+ 10 ml of solvent + 10 ml of solvent

filter filter

2. TESTING THE PH RANGE OF THE INDICATORPREPARATION ACID RANGE SOLUTION( TEST TUBE #1-#6)

13 test tube was labeled

9.0 ml distilled water was Placed except #1 & #13

Serial dilution for Acid range solution is made

10.0 ml of 0.1 M HC is placed in #1

Continue transferred 1.0 ml of diluted acid solution to the next test tubeuntil six acid solutions are prepared (Ph 1-6)

Ph7 (10 ml distilled water)

PREPARATION BASE RANGE SOLUTION(TES TUBE #13-#8)

Solution of base is prepared

10.0 ml of 0.1 M NaOH was placed in test tube #13. (pH13

1.0 ml of 0.1 M NaOH was transferred from test tube #13 to test tube#12 and thoroughly mixed.

Continue Serial dilution for Base range solution is made (ph 8-ph 13)

spot plate was labeled 1-13 for each indicator)

A few drops of solution is transfered

A few extract indicator is dropped in each solution

Color was observed

TESTING THE PH OF OTHER LIQUIDS

When the pH indicators has been determined

household chemicals was used to test their pH

RESULTTESTING THE PH RANGE OF THE INDICATOR

RED CABBAGE

TURMERIC

HOUSEHOLD CHEMICAL (RED CABBAGE)

HOUSEHOLD CHEMICAL (TURMERIC))

DISCUSSION

1)Red cabbage is a very good PH indicator but is loose its ability to indicated the PH over a couple of weeks or month depending on how you store the solution. Red cabbage juice indicator is easy to make, exhibits a wide range of colors, and can be used to make your own pH paper strips

Red cabbage extract PH indicator

ph 0-1 ph 2 ph 4 ph 5-8 ph 9 ph 10 ph 11-14

 

2. The best way to store turmeric over longer periods is to store it as powder. To use it just mix a bit of powder with water. 

Turmeric PH indicator

below ph 7.4 above ph 8.6

3.The turmeric indicator changes colour between roughly a pH of 7.4 and 8.6. If turmeric is exposed to neutral or acidic substances (those with a pH of less than 7.4) it will retain its yellow colouration. However, if turmeric is exposed to more alkaline substances (those with a pH greater than 8.6) it becomes a dark pink/red.

4.That’s because turmeric contains a yellow pigment called curcumin, which is pH sensitive. Its molecules change shape in solutions of different pH. They are yellow in solutions that are acidic, like orange juice and vinegar , but they turn dark red in solutions that are basic like laundry detergent.

5. The colour of anthocyanins changes with pH from a yellowy green in very alkaline solutions, to a blue-ish purple in neutral solutions, to bright pink in acidic solutions.

TESTING PH OF OTHER LIQUID Vinegar – acid (the color of vinegar turn to pink after added with

red cabbage and yellow color after added with turmeric)

Orange juice – acid (the color of orange juice turn to orange/light red after added with red cabbage and light yellow color after added with turmeric)

Toothpaste – base/alkaline (the color of toothpaste turn to purple after added with red cabbage and yellow color after added with turmeric)

REFERENCES

http://www.chemistryland.com/CHM107Lab/Lab1/Lab1PreparingCabbageExtract.htm

http://chemistry.about.com/od/acidsbase1/a/red-cabbage-ph-indicator.htm

http://sciencesquad.questacon.edu.au/activities/colourful_chemistry.html

REFERENCES http://www.abc.net.au/science/articles/2012/04/03

/3470205.htm?site=science/tricks http://tuxgraphics.org/npa/litmus-redcabbage-tum

eric-radish-ph-indicator/ http://www.ehow.com/how_8497638_make-turmeri

c-ph-indicator.html