La’Darion Roberts Period 3 LaSalle

 The Purpose of this lab is to measure the pH of Various household items using a natural indicator prepared from Cabbage Leaves. This demonstration will help with understanding the readings of a pH scale, and how to use indicators to determine the pH of a substance.

 knife  red cabbage leaves  1-cup measure  hot water  2 jars  clean white cloth  teaspoon  tape  3 sheets of plain white paper  pencil  ruler  10 clear plastic cups  white vinegar (CH3COOH)  baking soda (NaHCO3)  household ammonia  dropper  various household items

 Put ½ cup of finely chopped red cabbage leaves in a jar and add ½ cup of hot water. Stir and crush the leaves with a spoon. Continue the extraction until the water is distinctly colored.  Strain the extract through a piece of cloth into a clean jar. This liquid is your natural indicator.

 Tape three sheets of paper end to end. Draw a line along the center and label it at 5 cm intervals with the numbers 1 to 14. This is your pH scale.  Pour your indicator to about 1 cm depth into each of three plastic cups. To one cup, add several drops of vinegar

 to the second add a pinch of baking soda,  and to the third add several drops of ammonia.  ***The resulting colors indicate pH values of about 3, 9, and 11, respectively. Place these colored positions on your pH scale.

 Repeat Step 4 for household items: Lemon Juice, 2% Milk, Coffee, Mouthwash, Toothpaste, distilled water, laundry detergent(powder), dish washing soap

 What was the color of the indicator at acidic, neutral, and basic conditions?  The color of the indicator changed to a light pink/red and color when an acidic substance was added, it remained the same/turned lighter for the neutral(distilled water) and turned a deep green/blue for the basic. These colors closely resembled the colors on the pH scale.

 What chemical changes were responsible for the color changes?  The color changes occurred because each substance had a different concentration of [H+] and [OH-] ions, therefore causing the pH to be higher(basic) or Lower(acidic)

 Label the materials you tested as acidic, basic, or neutral.  Baking Soda- Acidic  Ammonia- Basic  Vinegar- basic  Milk- acidic  Lemon juice- acidic  Coffee- acidic  Water- neutral  Dish soap- basic  Mouth wash- Acidic  Toothpaste- Acidic  Laundry detergent- basic

 Which group contains items used for cleaning or for personal hygiene?  During the experiment, I noticed that the items used for cleaning are almost always Basic solutions, and the ones that we use for personal hygiene, (i.e. mouthwash, toothpaste, etc) are almost always acidic!