Question

Experiment 1: Neutralization of Acids and Bases

In this experiment, you will learn how to properly neutralize and dispose of acidic and base solutions. Remember, when a solution has a pH of 7, it is considered neutralized.

Experiment 1: Neutralization of Acids and Bases In this experiment, you will learn how to properly neutralize and dispose of acidic and base solutions. Remember, when a solution has a pH of 7, it is considered neutralized. Materials 5 mL 4.5% Acetic Acid (vinegar), C2H4O2 (1) 250 mL Beaker (1) 10 mL Graduated Cylinder (1) 100 mL Graduated Cylinder (8) Litmus Test Strips (Neutral) (2) Pipettes 0.5 g Sodium Bicarbonate (baking soda), NaHCO3 (2) Weigh Boats *Water *Permanent Marker *You Must Provide Procedure Use the permanent marker to label two of the weigh boats as A and C. Use the permanent marker to label a 250 mL beaker B. Set the containers in the order A, B, and C. Measure and pour approximately 5 mL of water into weigh boat “A”. Add 0.5 g sodium bicarbonate to beaker “B”. Use the 100 mL graduated cylinder to measure and pour 100 mL of water into beaker “B”. Gently pipette the solution up and down until the sodium bicarbonate is fully dissolved in the water. Leave this pipette in beaker B to mix the solution in future steps. Use the 10 mL graduate cylinder to measure and pour 5 mL acetic acid solution to weigh boat “C”. Develop a hypothesis as to what the pH of the contents of each container is. Record your hypothesis in Post-Lab Question 1. Use the litmus test strips to determine if the substances in containers A - C are acidic, basic, or neutral. This is accomplished by briefly dipping an unused strip of the litmus paper in each of the weigh boats. Record your color results in Table 2. Record results immediately after dipping. The litmus paper may become darker as it dries. Pipette 1 mL of acetic acid from weigh boat “C” into beaker “B”. Ensure the transfer pipette does not touch the solution in beaker “B”. Gently pipette the solution in beaker B with its pipette to mix. Test the pH of beaker “B” using new litmus paper and immediately record your result in Table 3. Repeat Steps 10 - 12 four more times until all the acetic acid has been added to beaker “B”. Table 2: Initial Litmus Test Results Container Chemical Contents Litmus Results Additional Observations A B C Table 3: Neutralization Amount of Acid Litmus Results 1 mL 2 mL 3 mL 4 mL 5 mL Post-Lab Questions State your hypothesis (developed in Step 8) here. Be sure to include what you think the pH will be, and why. What is a neutralization reaction? When might neutralization reactions be used in a laboratory setting? At what point was the solution in beaker “B” neutralized? What do you think would have been the results if a stronger solution of sodium bicarbonate was used? Would it take more or less to neutralize? What about a weaker concentration of sodium bicarbonate?

Procedure

1. Use the permanent marker to label two of the weigh boats as A and C.
2. Use the permanent marker to label a 250 mL beaker B.
3. Set the containers in the order A, B, and C.
4. Measure and pour approximately 5 mL of water into weigh boat “A”.
5. Add 0.5 g sodium bicarbonate to beaker “B”.
6. Use the 100 mL graduated cylinder to measure and pour 100 mL of water into beaker “B”. Gently pipette the solution up and down until the sodium bicarbonate is fully dissolved in the water. Leave this pipette in beaker B to mix the solution in future steps.
7. Use the 10 mL graduate cylinder to measure and pour 5 mL acetic acid solution to weigh boat “C”.
8. Develop a hypothesis as to what the pH of the contents of each container is. Record your hypothesis in Post-Lab Question 1.
9. Use the litmus test strips to determine if the substances in containers A - C are acidic, basic, or neutral. This is accomplished by briefly dipping an unused strip of the litmus paper in each of the weigh boats. Record your color results in Table 2. Record results immediately after dipping. The litmus paper may become darker as it dries.
10. Pipette 1 mL of acetic acid from weigh boat “C” into beaker “B”. Ensure the transfer pipette does not touch the solution in beaker “B”.
11. Gently pipette the solution in beaker B with its pipette to mix.
12. Test the pH of beaker “B” using new litmus paper and immediately record your result in Table 3.
13. Repeat Steps 10 - 12 four more times until all the acetic acid has been added to beaker “B”.

Table 2: Initial Litmus Test Results
Container	Chemical Contents	Litmus Results	Additional Observations
A
B
C

Table 3: Neutralization
Amount of Acid	Litmus Results
1 mL
2 mL
3 mL
4 mL
5 mL

Post-Lab Questions

1. State your hypothesis (developed in Step 8) here. Be sure to include what you think the pH will be, and why.

2. What is a neutralization reaction?

3. When might neutralization reactions be used in a laboratory setting?

4. At what point was the solution in beaker “B” neutralized?

5. What do you think would have been the results if a stronger solution of sodium bicarbonate was used? Would it take more or less to neutralize? What about a weaker concentration of sodium bicarbonate?

Answer 1

Compound in Container A is Neutral.

Compound in Container B is Basic.

Compound in Container C is Acidic.

You've to Complete Table 3 experimentally, it can't be completed theoretically.

Post Lab Questions :

• pH of the Compound in Container A is 7, because it's Neutral.

pH of the Compound in Container B is greater than 7, because it's Basic.

pH of the Compound in Container C is less than 7, because it's Acidic.

• The Reaction between an ACID and a BASE to form SALT and WATER is called NEUTRALIZATION REACTION.
• NEUTRALIZATION reactions can be used in the lab, to determine the strength of an Unknown Acid/ Base.
• The NEUTRALIZATION point of NaHCO_​​3 in Container C should be determined experimentally, it can't be determined theoretically.
• If a stronger Solution of NaHCO₃ is used, it would take more amount of Acetic Acid to neutralize the Solution. Accordingly, if a weaker solution of NaHCO_​​3 ​​​​​​​is used, it would take less amount of Acetic Acid to neutralize.