Volumetric Analysis Prac Essay

Aim:
To determine the concentration in %w/v of commercial hydrogen peroxide solution by titrating against potassium permanganate solution of known concentration.
Materials:
5mL 6% hydrogen peroxide solution (H2O2)
Distilled water
200mL 0.0200 mol L-1 potassium permanganate (KMnO4) solution
40mL 2.00 mol L-1 sulfuric acid
4 x 100mL conical flasks (calibrated to the nearest 25mL)
1 x 50mL volumetric burette (calibrated to the nearest 0.2mL)
1 x 250mL beaker (calibrated to the nearest 50mL)
1 x 200mL volumetric flask (calibrated to the nearest 200mL)
1 x 10mL measuring cylinder (calibrated to the nearest 0.2mL)
1 x 1mL pipette (calibrated to the nearest 1mL)
1 x Retort stand
1 x Burette clamp
1 x White tile (approximately 15cm x 15cm)
1 x Funnel
Procedure:
1. 5mL of 6% H2O2 solution was added to the 200mL volumetric flask
2. The 200mL volumetric flask was then filled half way with distilled water and swirled to mix the solution.
3. The volumetric flask was then filled to the calibration mark with distilled water.
4. The volumetric flask was then stoppered and inverted.
5. The burette was first rinsed with distilled water and then rinsed with the KMnO4 solution.
6. The titration apparatus was then setup as shown in figure 1.
7. The 20mL pipette was washed with distilled water and then washed with the H2O2 solution.
8. A 20mL aliquot of the diluted H2O2 solution was collected using a 20mL volumetric pipette.
9. The 20mL aliquot was then pipetted into a 100mL conical flask.
10. 10mL sulfuric acid was then added to the conical flask via
11. The burette was then filled with KMnO4 solution from the 250mL beaker. A funnel was used to avoid spillage.
12. Some of the KMnO4 solution was let out to remove any bubbles in the tip of the burette and the initial volume was recorded to the nearest 0.05ml.
13. The 100mL conical flask containing the H2O2 solution was placed underneath the burette on top of a white tile.
14. The KMnO4 solution was titrated using the burette.
15. The conical flask is swirled constantly. Distilled water is used to wash the sides of the flask to flush down any residual KMnO4
16. The burette was slowed as the purple colour took longer to become colourless.
17. The titration was terminated by completely turning off tap once there was a permanent colour change.
18. The final volume was then recorded and the titre value was calculated.
19. Steps 8-18 was then repeated until at least 3 concurrent titre values were recorded.

Safety Risk
Hazard Presented
Prevention/Treatment
Glass Breakage and sharps
Breakage of glass presents a risk of cuts.
Care should be taken handling glassware. All glassware should be kept away from edge of workspaces to prevent dropping. Closed in shoes are required to prevent stepping on broken glassware. Surrounding students and the supervisor need to be notified in the event of breakage. The breakage should then be cleaned up appropriately
Spillage
Spillage of liquids present a slippage hazard.
Aprons were worn to prevent spillage onto clothes. Care should be taken when handling liquids and kept away from workspace edges. In the event of spillage, surrounding students and the supervisor need to be notified. The spillage should then be cleaned up appropriately.
Eye Irritant
The chemicals used can be an irritant if they come into contact with eyes.
Safety glasses were worn to prevent this. In the event of chemicals coming into contact with eyes, if possible use an eye-rinse station. Notify the supervisor in charge and seek medical attention.
Corrosion
Hydrogen peroxide is a caustic oxidising agent which can cause blistering when in contact with skin.
Care should be taken when handling hydrogen peroxide as to avoid spills and contact with skin. In the event of skin contact, the area of contact should be immediately washed with water. In the event of blistering, the supervisor should be notified and seek medical assistance.

Observations:
Before Titration
Diluted H2O2 solution was

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