Analysis of a Commercial Bleach
Analysis of a Commercial Bleach
Purpose: The purpose of this lab is to determine the amount of sodium hypochlorite (NaClO) in commercial bleach. This can be done by forming triiodide ions. To make the measurement more accurate, starch was added to help determine the endpoint of the solution. The significance of this lab is that industry can use these techniques to determine the amount of NaClO in the bleach of the rival industry and improve it.
Hypothesis: The hypothesis is that, an accurate determination of NaClO in commercial bleach can be done. By mixing the acidified iodide ion to the hypochlorite solution, the iodide is oxidized to iodine which forms complex triiodide ions that give the red-brown color to the solution. Because the endpoint of the titration of triiodide is hard to determine, starch is added to give the solution a dark blue color. If starch was not added, the color would be turning from yellow to clear. It is quite hard to distinguish between the two colors and therefore, starch was added so the color would turn from yellow to dark blue. This makes it a lot easier to determine the endpoint.
Materials:
Distilled water- 100 mL
5% bleach (NaClO)- 5 mL
3 M Hydrochloric acid (HCl)- 6 mL
0.100 M Sodium thiosulfate (Na2S2O3)- 100 mL
2% Starch solution- 3 mL
Potassium iodide (KI)- 6g
Burette
Burette clamp
Ring stand
Small funnel
6 pipettes
0.0001-g precision balance
3 wash glasses
Spatula
Rubber spatula
6 125-mL Erlenmeyer flasks
Size 2 rubber stopper
Stirring rod
10-mL graduated cylinder
25-mL beaker
Procedures:
1.) Measure out 5 mL of NaClO into a 125-mL Erlenmeyer flask
2.) Add 95 mL of distilled water to the flask
3.) Mass out 2 g of solid KI
4.) Transfer 25 mL of the diluted NaClO in the flask to another 125-mL Erlenmeyer flask
5.) Repeat step 3 and 4 for two more times
6.) Label the flask: Trial 1, Trial 2, Trial 3
7.) Add 2 g of solid KI to the Trial 1 flask
8.) Swirl the flask to dissolve the KI
9.)
Purpose: The purpose of this lab is to determine the amount of sodium hypochlorite (NaClO) in commercial bleach. This can be done by forming triiodide ions. To make the measurement more accurate, starch was added to help determine the endpoint of the solution. The significance of this lab is that industry can use these techniques to determine the amount of NaClO in the bleach of the rival industry and improve it.
Hypothesis: The hypothesis is that, an accurate determination of NaClO in commercial bleach can be done. By mixing the acidified iodide ion to the hypochlorite solution, the iodide is oxidized to iodine which forms complex triiodide ions that give the red-brown color to the solution. Because the endpoint of the titration of triiodide is hard to determine, starch is added to give the solution a dark blue color. If starch was not added, the color would be turning from yellow to clear. It is quite hard to distinguish between the two colors and therefore, starch was added so the color would turn from yellow to dark blue. This makes it a lot easier to determine the endpoint.
Materials:
Distilled water- 100 mL
5% bleach (NaClO)- 5 mL
3 M Hydrochloric acid (HCl)- 6 mL
0.100 M Sodium thiosulfate (Na2S2O3)- 100 mL
2% Starch solution- 3 mL
Potassium iodide (KI)- 6g
Burette
Burette clamp
Ring stand
Small funnel
6 pipettes
0.0001-g precision balance
3 wash glasses
Spatula
Rubber spatula
6 125-mL Erlenmeyer flasks
Size 2 rubber stopper
Stirring rod
10-mL graduated cylinder
25-mL beaker
Procedures:
1.) Measure out 5 mL of NaClO into a 125-mL Erlenmeyer flask
2.) Add 95 mL of distilled water to the flask
3.) Mass out 2 g of solid KI
4.) Transfer 25 mL of the diluted NaClO in the flask to another 125-mL Erlenmeyer flask
5.) Repeat step 3 and 4 for two more times
6.) Label the flask: Trial 1, Trial 2, Trial 3
7.) Add 2 g of solid KI to the Trial 1 flask
8.) Swirl the flask to dissolve the KI
9.)