APPLICATION: MAKING pH INDICATOR

DEPARTMENT OF BIOLOGY

FACULTY OF SCIENCE & MATHEMATICS

UNIVERSITI PENDIDIKAN SULTAN IDRIS

SBK3013

PRINCIPLE IN BIOCHEMISTRY

LABORATORY PROJECT 1

APPLICATION: MAKING pH INDICATOR

NAME	MATRIC NO.
MUHAMMAD FARIS BIN ISMAIL SAZEMI	D20141067089
MAYURIE PHUTHARANT A/P SURIN	D20141067078
NUR AFIQAH SYAHMINA BT MOHD KAMAL	D20141067091

GROUP: A

LECTURER’S NAME: DR. ROSMILAH MISNAN

INSTRUCTOR NAME: NUR ATIEKAH BT AZAHARI

INTRODUCTION

pH is the measure of the concentration of hydrogen ions in a solution. In this experiment we used red cabbage and common flower which contain indicator pigment as a test paper. The extraction of those natural indicators will be used to test the presence of acid or base in the household products. The changes color depending on the pH of the solution it is mixed with. The color scale obtained were used to determine the pH of the products.

MATERIAL

·         HCl solution

·         NaOH solution

·         Acetone

·         Purple cabbage

·         Purple flower

·         Household chemical ( toothpaste, detergents, soap and conditioner)

 PROCEDURE

Extracting the indicator

1. Purple cabbage was smashed up until it crushed.
   
   
    
2.    10 mL of acetone was added into the purple cabbage
   
   
3. Then extract from the purple cabbage was been filtered and the extract from the purple cabbage was collected.
   
    
   
4. Step 1 until 3 was repeated by using Purple flower 

           

Testing the pH range of the indicator 

1.  13 test tube was labelled as test tube 1 until test tube 13 and prepared for two set;
   set A and set B.
2. Next step followed as a table below:
3. After that, the solution in test tube set A was divided into half and transfer to the
   test tube set B
   
   
   

   Test tube	Distilled water	Acid or Base	pH
   1	-	10 ml of 0.1 M HCl	1
   2	9 ml	1 ml acid from test tube 1	2
   3	9 ml	1 ml acid from test tube 2	3
   4	9 ml	1 ml acid from test tube 3	4
   5	9 ml	1 ml acid from test tube 4	5
   6	9 ml	1 ml acid from test tube 5	6
   7	10 ml	-	7
   8	9 ml	1 ml NaOH from test tube 9	8
   9	9 ml	1 ml NaOH from test tube 10	9
   10	9 ml	1 ml NaOH from test tube 11	10
   11	9 ml	1 ml NaOH from test tube 12	11
   12	9 ml	1 ml NaOH from test tube 13	12
   13	-	10 ml of 0.1 M NaOH	13

4. Three drops of purple cabbage extract was added to the test tube set A and three drop of purple flower extract was added into test tube set B
5. The pH was observed by compared with the colour of both indicator change

Testing the pH of household chemicals 

1. All the household chemicals placed into white tile
2. Each one type of household chemicals are test with purple cabbage and purple flower extract.
3. The colour changes was recorded and the pH value had been compared with the indicator from above procedure.

RESULT 

Testing the pH range of the indicator 

Purple cabbage extract 

Purple flower extract 

Testing the pH of household chemicals 

Household Chemicals	pH  Purple Cabbage	pH Flower
Toothpaste (Colgate)	11	11
Detergents  (Attack Perfume)	11	12
Soap (Mareah)	6	6
Conditioner (Sunsilk)	3	4
Soap (Shurah)	7	7

DISCUSSION

In this experiment, we were doing the pH indicator. A pH indicator is a substance which has one colour when added to an acidic solution and a different colour when added to an alkaline solution. In this experiment, were using natural substances such as red cabbage and boungainvillea.

Red cabbage is useful as a pH indicator because the leaves contain a pigment molecule from the family of anthocyanins (shown below) which are responsible for many of the red/purple/blue colors observed in fruits and vegetables. In neutral solutions, the color observed is purple. As the solution becomes more acidic a red color results. Increasing the pH in basic solutions changes the color from blue to green and at high pH the solution is observed as greenish-yellow.

We were instructed to bring any five chemical household to detect either daily product we use is acidic or basic. We brought Colgate, Attack Perfume (clothes washing soap), Mareah (body washing soap), sunsik (conditioner) and lastly Syurah (face washing soap). All of those product will be placed in a white tile and the natural indicator (the cabbage and boungainvillea indicator) will be mixed to see the colour changes. The colour changes will be compared with the known pH of the natural indicator that we do earlier.

For the red cabbage indicator, the pH of the Colgate is 11 when it is compared with the indicator that we have made earlier. The same thing goes to the clothes washing soap. The pH that we got is 11 which mean that it has basic properties. For the body washing soap, the pH that we got after making comparison with the natural pH indicator is 6 which mean that it is acidic. The face washing soap show the pH 7 which is natural. It is neither basic nor acidic. Among all of the household chemical that we bring, Sunsilk is the only one that shows a very strong acid content in it.

For the boungainvillea indicator, the pH of the Colgate is 11 which is the same as the pH in the red cabbage indicator.  The clothes washing soap shows a little bit different in value. In bouigainvillea indicator, it shows pH 12, whereas in red cabbage indicator, it shows pH of 11. For the body washing soap, the pH for both substances is the same that is 6. Sunsilk also shows a little bit different in value. In red cabbage indicator, the pH value that we get is 3, meanwhile when mixed with the bouigainvillea indicator, the pH is 4. Lastly, the face washing soap, it shows the same pH that is natural or pH 7.

CONCLUSION

From this experiment we can conclude that both red cabbage and flower are best natural indicator to refer to since the value of pH obtained are almost the same when tested with household solution. Both indicator able to indicate basic, acidic and neutral pH when tested with different household products.

REFERENCES

Anonymous. (2012). Red Cabbage Juice: A Homemade pH Indicator. Access from http://www.carolina.com/teacher-resources/Interactive/red-cabbage-guice-homemade -ph-indicator/tr10851.tr  on March 23rd, 2017.

Helmenstine, A. M. (2013). Red Cabbage pH Indicator . Access from http://chemistry.about.com/od/acidsbase1/a/red-cabbage-ph-indicator.htm  on March 23rd, 2017.

Katherine J. Denniston, Joseph J. Topping, Kim R. Woodrun, Robert L. Caret.(2013). General, Organic and Biochemistry.  United State of America: McGraw-Hill Education

Martin S. Silberberg (2013). Chemistry: The Molecular Nature of Matter and Change. NewYork: McGraw-Hill Companies Inc.

Zumdahl, Steven S. (2009). Chemical Principles (6th ed.). New York: Houghton Mifflin Company