ACID-BASE TITRATION

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I. OBJECTIVES

1. To learn the techniques in acid-base titration; and

2. To determine the concentration of an acid or a base by the process of titration.

• FEU East Asia College

• EE 201411581

II. MATERIALS AND REAGENTS

Quantity Item Reagents

1 50 – mL graduated cylinder 0.1 N NaOH

1 10 – mL graduated cylinder HCl solution

1 Burette Distilled Water

1 Burette Clamp phenolphthalein

1 250 – mL beaker

1 Iron Stand

1 150 – mL Erlenmeyer Flask

III. SET-UP/DIAGRAMS/ILLUSTRATIONS

Figure 1

IV. PROCEDURES:

1. Obtain a burette and clean it, the burette must be clean in order to deliver the calibrated volume.

Cleaning of the burette can be accomplished by filling it with warm detergent solution, allow to

stand for about 5 minutes then rinse well with tap water followed by distilled water. Test the burette

to determine if water runs freely without leaving droplets of water upon sides.

· Finally rinse it 2 to 3 times with 5 to 10 mL portion of the solution to be placed in it. The

rinsing with the solution is done by holding the burette in a nearly horizontal position and

rotated so that all portions of the wall are wet with solution.

2. Prepare the set up of apparatus. All volumes must be measured using burettes.

3. Deliver exactly 10 mL of HCl solution to a clean Erlenmeyer flask.

4. Add 2 to 3 drops of phenolphthalein indicator and about 25 mL of distilled water to the flask.

5. Pour the standard 0.1 N NaOH solution into the burette.

6. Titrate the acid in the flask with the base until the solution turns to light pink which persists for at

least 30 seconds.

7. Record the volume of the base.

8. Repeat the titration using another 10 ml acid.