Acid Base Indicator Lab
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1
2Chemistry
2015
Chemistry
2015
Data:
pH Lab
Name __________
Test
Universal pH paper
Red Litmus
Blue Litmus
Cabbage
Chemical
Juice
Introduction
Color
pH
Indicator
The measure of the concentration of hydrogen ions in a solution is the pH. Solutions with a pH below
7 are acidic. Solutions with a pH above 7 are basic. A pH of 7 represents a neutral solution, one that
H
O
2
is neither an acid nor a base. Pure water has a pH of 7. The pH scale is from 0 to 14. Solutions can
be identified as being acidic or basic by testing them with certain indicators. Some indicators (pH
test paper) can be used to determine the specific pH of a solution as its color changes within a
HCl
specific range. Red and blue litmus papers indicate whether a solution is an acidic or a basic solution.
Red litmus paper turns blue in a basic solution. Blue litmus paper turns red in an acidic solution.
NaOH
Vinegar
NaCl
(aq)
NaHCO
3(aq)
Purpose: To use various indicators to determine the pH of common substances.
Dish Soap
Procedure:
Materials:
Alcohol
Blue Litmus, Red Litmus, Universal Indicator, Reaction Surface, Cabbage, Goggles, Chemicals
Ammonia
1. Put on safety goggles.
2. Cut small pieces (2 cm) of blue litmus paper, red litmus paper, and pH paper and place them in
separate petri dishes.
3. Put 2 drops of a solution in each of the wells of the first row in the well tray. Write the name of
st
the solution in the 1
column of the data table.
4. Use other solutions to fill the second third and fourth rows. Write the name of the solutions in
st
the 1
column of the data table (next page).
5. Insert a piece of blue litmus paper into the first solution in the first column. Immediately observe
the color of the paper. Record the color by shading the squares with colored pencils.
pH scale
6. Repeat step 5 for the other solutions.
7. Repeat step 5 using red litmus paper in the second column of the well tray.
___________________________________________________________
8. Repeat step 5 using pH paper in the third column of the well tray. Use the color chart to
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
…….determine the pH number of each solution and put this number in the appropriate spot on the
…….data table.
9. Repeat step 5 using the cabbage juice. See directions on the back.
Post‐Lab Questions
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