Titration
Essay by Mehnaz Mohtar • August 7, 2016 • Lab Report • 1,191 Words (5 Pages) • 1,429 Views
INDIVIDUAL PRACTICAL REPORT – CITRIC ACID CONTENT IN ORANGE JUICE
Name: Mehnaz Zeinab Binti Wan Mohtar Date: 10 APRIL 2016
Student ID: 1511170522 Class: Bondi
Partner: Janariah binti Ahmad Reza
- Results
- Aim: To determine mass percentage (% w/w) of acid in orange using material as shown below;
-Orange juice
-NaOH solution
-Phenolphthalein indicator
1.2 Quick overview;
The volume of sodium hydroxide to complete neutralization were determined by the mixture in the conical flask to change colour.
20mL of orange juice and 3 drops of phenolphthalein were put in a conical flask. Sodium hydroxide solution were titrated drop by drop to react with the citric acid in the conical flask.
Below are the equation for the reaction between citric acid and NaOH;
H3C6H5O7 + 3NaOH → Na3C6H8O7 + 3H2O
[pic 1][pic 2][pic 3]
1.3 Data Collection;
Orange juice | Mass of orange juice (g) | Initial volume of orange juice (mL) | Volume of sodium hydroxide used (mL) | Concentration of sodium hydroxide |
First | 19.3347 | 20 | 3.5 | 1.0 |
Second | 19.4709 | 20 | 3.6 | 1.0 |
Third | 19.4894 | 20 | 3.6 | 1.0 |
Fourth | 19.5957 | 20 | 4.1 | 1.0 |
1.4 Data measurements of conical flask before start titration;
Photos | Details and explanation |
[pic 4] | The electronic balance needs to be calibrate to re-zero in order to get accurate mass and prevent zero error. |
[pic 5] | The initial mass of the first conical flask filled with 20mL of orange juice is 19.3347g |
[pic 6] | The initial mass of the second conical flask filled with 20mL of orange juice is 19.4709g |
[pic 7] | The initial mass of the third conical flask filled with 20mL of orange juice is 19.4894g |
[pic 8] | The initial mass of the fourth conical flask filled with 20mL of orange juice is 19.5957g |
1.5 Data measurements of sodium hydroxide level after titration;
Photos | Details |
Initial reading of sodium hydroxide in the burette: 0 mL | |
Pre-test of experiment was held so that we are familiar with the procedures. The measurement of the sodium hydroxide level obtained based on the end point was 4.1mL. The data obtained are considered to be the fourth attempt. | |
[pic 9] | Mixture reached end point at 7.3mL. The volume of the sodium hydroxide titrated is as shown below; 7.3-4.1 mL = 3.2mL |
[pic 10] | Mixture reached end point at 10.9mL The volume of sodium hydroxide titrated is as shown below; 10.9-7.3 mL = 3.6mL |
[pic 11] | Mixture reached end point at 14.5mL The volume of sodium hydroxide titrated is as shown below; 14.5-10.9 mL = 3.6mL |
1.6 The final colour change of the orange juice in the conical flask
Photos | Details |
[pic 12] Orange in colour |
[pic 13] Orange to pale yellowish |
[pic 14] Orange to very pale orangey |
[pic 15] Orange to pale orangey |
1.7 Discussion
1.6.1 Rinsing procedures for glass wares
Photos | Details and explanation |
Burette | Cleans with sodium hydroxide solution. This is because we want to put the solution into the burette. Hence, this will not left any remaining foreign substances other than just presence of sodium hydroxide solution. |
Pipette | Rinsed with distilled water to clean the foreign substances. This is essential as we want to measure the distilled water accurately to be put in the conical flask |
Conical flask | Rinsed with distilled water to clean the foreign substances to free from any contamination and prevent any other substance to interrupt the neutralization. |
Measuring cylinder | Rinsed with distilled water so that the surface and the inner walls of the measuring are free from dust and unwanted material. |
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