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Title: Investigation of Acids and Bases

Purpose: To investigate various properties of Acids and Bases

Introduction: Discuss acids and bases

Procedure:

Part I: Acids, Bases, and Indicators

1. Obtain five small test tubes and add approximately one inch of the following solutions to each of them: 0.1 M HCl, 0.1 M HC2H3O2, 0.1 M NH3, 0.1 M H2O, 0.1 M NaOH.

2. To each test tube, add one drop of universal indicator and swirl gently.

3. Obtain several strips of both blue and pink Litmus paper. Place a small drop of each of the solutions onto both colors of Litmus paper and record the results.

4. Using an extra test tube, prepare one solution at a time of the following substances (rinse the test tube in between trials): NaHCO3 (baking soda), a soft drink, vinegar, bleach, soap. To make each solution, simply place a few drops (or a pea size scoop) into the test tube and add approximately an inch of distilled water. Compare each solution that you made against the color of the five solutions you made in step 1.

 

Part II: Reaction of Acid and Metal

1. In a small test tube, obtain a small sample of concentrated HCl from your teacher. To this sample, add a small piece of Mg ribbon. As the ribbon dissolves, hold a lit match over the top of the test tube to check to see if the gas being generated is flammable.

Part III: Reaction of Acids and Bases

1. Obtain a larger test tube and add approximately inch of 0.1 M HCl to it. Add about 2-3 drops of universal indicator to this test tube. To this same test tube, slowly add a solution of 0.1 M NaOH and note the color change. Continue adding the NaOH until the color seems to be constant. Now, to the same test tube, add 0.1 M HCl and see if you can make the color in the test tube change back to what it was originally.

Data: Record all of your observations in one or more data tables.

Analysis:

1. Classify all of the substances used in Part I of the lab as an acid or base.

Questions:

1. Give the proper name of the following substances used in the lab: HCl, HC2H3O2, NH3, NaOH.

2. What is the relationship between the color of the universal indicator and whether a solution contains an acid or base?

3. What is the relationship between the color of Litmus paper and whether a solution contains an acid or base?

4. Using evidence from Part III of the lab, do you think there is a relationship between the amount of acid or base in solution and the color of universal indicator? Explain.