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 detergentbasic

 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!