Lab 9: Analysis Of Commercial Bleach
Lab 9: Analysis of Commercial Bleach
Introduction
Many common products are effective because they contain oxidizing agents.
Some products, which contain oxidizing agents, are bleaches, hair coloring agents, scouring powders, and toilet bowl cleaners. The most common oxidizing agent in bleaches is sodium hypochlorite, NaClO (or NaOCl). Commercial bleaches are made by bubbling chlorine gas into a sodium hydroxide solution. Some of the chlorine is oxidized from the molecular form (Cl2) to the hypochlorite ion, ClO-. Some of the molecular form is also reduced to the chloride ion, Cl-. This type of reaction, where the same type of element is both oxidized and reduced, is called a disproportionation reaction. The solution remains strongly basic. The net …show more content…
Measure the potassium iodide.
Weigh out approximately 2 g of solid KI. This amount is a large excess over that which is needed.
3. Oxidize the iodide ion with hypochlorite ion.
Using a graduated cylinder, transfer 25 mL of the dilute bleach into an
Erlenmeyer flask. Add the KI and about 25 mL of distilled water. Swirl to dissolve the KI. Working in a fume hood and slowly with swirling, add approximately 2 mL of 3 M HCl. The solution should be a dark yellow to redbrown from the presence of I3
- complex.
4. Titrate the iodine.
Rinse the buret with distilled water and then three times with small portions of your 0.10 M sodium thiosulfate solution. Then, fill up the buret with the 0.10 M sodium thiosulfate solution. Titrate the bleach-iodine mixture in your
Erlenmeyer flask until the iodine color becomes yellow. Add one dropperful of starch solution. The blue/black color of the starch-iodine complex should appear. Continue the titration until one drop of Na2S2O3 solution causes the blue color to disappear. Record the final buret reading.
5. Repeat
Repeat the titration beginning with step 2 two more times.
Disposal
The solutions may safely be flushed down the drain with a large excess of
Introduction
Many common products are effective because they contain oxidizing agents.
Some products, which contain oxidizing agents, are bleaches, hair coloring agents, scouring powders, and toilet bowl cleaners. The most common oxidizing agent in bleaches is sodium hypochlorite, NaClO (or NaOCl). Commercial bleaches are made by bubbling chlorine gas into a sodium hydroxide solution. Some of the chlorine is oxidized from the molecular form (Cl2) to the hypochlorite ion, ClO-. Some of the molecular form is also reduced to the chloride ion, Cl-. This type of reaction, where the same type of element is both oxidized and reduced, is called a disproportionation reaction. The solution remains strongly basic. The net …show more content…
Measure the potassium iodide.
Weigh out approximately 2 g of solid KI. This amount is a large excess over that which is needed.
3. Oxidize the iodide ion with hypochlorite ion.
Using a graduated cylinder, transfer 25 mL of the dilute bleach into an
Erlenmeyer flask. Add the KI and about 25 mL of distilled water. Swirl to dissolve the KI. Working in a fume hood and slowly with swirling, add approximately 2 mL of 3 M HCl. The solution should be a dark yellow to redbrown from the presence of I3
- complex.
4. Titrate the iodine.
Rinse the buret with distilled water and then three times with small portions of your 0.10 M sodium thiosulfate solution. Then, fill up the buret with the 0.10 M sodium thiosulfate solution. Titrate the bleach-iodine mixture in your
Erlenmeyer flask until the iodine color becomes yellow. Add one dropperful of starch solution. The blue/black color of the starch-iodine complex should appear. Continue the titration until one drop of Na2S2O3 solution causes the blue color to disappear. Record the final buret reading.
5. Repeat
Repeat the titration beginning with step 2 two more times.
Disposal
The solutions may safely be flushed down the drain with a large excess of