Acid-Base Indicator Lab
Purpose: To use various indicators to identify acids and bases.
Materials:
pH paper litmus paper, red and blue
2 pieces of Magnesium metal universal indicator safety goggles 2 unknown solutions
well plate
Procedure: Part 1
1. Fill 5 of the well plates with 5 drops of unknown solution #1.
2. Fill 5 of the well plates with 5 drops of unknown solution #2.
3. Place one strip of the red litmus paper in well 1 of unknown 1 and 2. Record your results in the chart below.
4. Place one strip of blue litmus paper in well 2 of unknown 1 and 2. Record your results in the chart below.
5. Place 3 drops of universal indicator in well 3 of unknown 1 and 2. Record your results in the chart below.
6. Place a strip of pH paper in well 4 of unknown 1 and 2. Record your results in the chart below.
7. Place one strip of metal in well 5 of unknown 1 and 2. Record your results in the chart below.
Test / Unknown 1 / Unknown 2 / pHRed litmus paper / X
Blue litmus paper / X
Universal indicator / Unknown 1 =
Unknown 2 =
pH paper / Unknown 1 =
Unknown 2 =
Magnesium metal / X
Procedure: Part 2
8. Place 5 drops of each of the known solutions into the 5mL plastic cups.
9. Pick ONE of the indicators you used in Part 1 and use it to test each of the unknown solutions. Record your observations and the pH of each solution in the table below. Before you pick your indicator, think about which one can give you the required information.
Substance / Observation (what color did the indicator turn?) / pH / Circle oneVinegar / Acid Base
Baking Soda / Acid Base
House cleaner / Acid Base
Vitamin C / Acid Base
Conclusion:
1. Is unknown solution 1 an acid or a base? How do you know this?
2. Is unknown solution 2 an acid or a base? How do you know this?
Analysis:
3. For the second part of the lab, which indicator did you pick to test your 4 known solutions? Why did you pick this indicator?
4. Which of the 4 indicators that you used do you feel is the most useful? Why did you choose this indicator?