McKenzie Sluder Section 125

Experiment 6
Purpose: To weigh duplicate samples, cool the solution at room temperature and then heat and boil the mixture to change the mixture into green, then yellow. Then calculate the molarity of HCL.
Introduction: Titration is used to determined for the molarity of an unknown substance. The process begins when you add a little addition of a solution that is called the second solution until the solute in the second unknown solution has reacted. The indicator is added in to the titration technique when we have finished titration. The indicator we used is phenolphthalein. This indicator should be used with a buret.
Procedure:
Standardization of 0.10M HCL
1. Weigh .15 grams of dried Na2CO3.
2. Dissolve sample in 100mL of distilled water, stir/heat if needed.
3. Add 5-6 drops of bromocresol green indicator until the solution turns blue.
3. Put HCL inside the buret and titrate the solution until a green color is reached (be careful to not over titrate it).
4.Once green color is reached, heat and broil the Co2. The color should return back to blue once this is completed.
5. Let it cool to room temperature, Once cooled, continue the titration of HCL until a yellow color is reached.
6. Calculate the molarity of the HCL.

Procedure:
Standardization 0.10M NahOH
1. Weigh 0.50 grams of dried standard potassium hydrogen phthalate (KHP). Dissolve into a sample of 100mL of distilled water.
2. Add 4-5 drops of phenolphthalein indicator. Titrate through a buret with NaOH until the solution turns a pink color.
3. Calculate the molarity of NaOH solution.

Repeat each standardization 3 times.

Results:
Standardization of HCL
Trial
HCL
Moles
Liters
Molarity
1
28.5mL
31.5
.031
.08
2
29mL
32
.032
.14
3
28mL
27.2
.027
.10
Average Molarity: .0931

Standardization of NaOH
Trial
NaOH
Moles
Liters
Molarity
1
31.5mL
.5
.031
5
2
29mL
20.5
.027
28.2
3
28.2mL
.076
.028
.0851
Average Molarity: .0808

Discussions and Questions:
During the procedure the first time we did the standization of the HCL, we accidently mixed the Na2CO3 into regular tap water. Once we