Identifying pH Using Natural Sources as Indicators

La’Darion Roberts
Period 3
 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
Strain the extract
through a piece of cloth
into a clean jar. This
liquid is your natural
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
to the second add a
pinch of baking soda,
 and to the third add
several drops of
 ***The resulting colors
indicate pH values of
about 3, 9, and 11,
respectively. Place
these colored
positions on your pH
 Repeat
Step 4 for
household items:
Lemon Juice, 2%
Milk, Coffee,
distilled water,
, dish washing
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
water) and turned a
deep green/blue for
the basic. These
colors closely
resembled the colors
on the pH scale.
 What
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
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 detergentbasic
 Which
contains items used
for cleaning or for
personal hygiene?
 During
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

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