Balancing a Redox Equation – I-/ IO3Chemicals and Equipment Needed
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d-H2O
0.05 M KI – H1
These solutions will probably need to be made and put into new bottles
0.05 M KIO3 – H1
Dropper bottle of 6 M H2SO4 – K2
Hexane – R4
3-100 mL graduated cylinders – Q3
Stoppers for the cylinders – U3
Separatory funnel – P5
Ground glass stopper for funnel – U4
Short ring stand and iron ring
White background – A1
Preparation
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This demonstration uses 0.005 M solutions of KI and KIO3:
o Pour 5 mL 0.05 M KI into one of the graduated cylinders, dilute to 50 mL with d-H2O. Stopper and
label base.
o Follow same procedure to make 0.005 M KIO3 solution.
Measure out 50 mL hexane in the last graduated cylinder, stopper and label base.
On delivery: slip the separatory funnel through the iron ring and make sure it is secure. Place the white
background behind and set the cylinders and dropper bottle to the sides.
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0.005 M
KI
0.005 M
KIO3
40
hexane
6M
H2SO4
Revised Spring 2015
AMM
Presentation
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Pour the KI (aq) and KIO3 (aq) into the separatory funnel and shake to mix.
o We expect I- to reduce the IO2- ion to I2, which would yield an orange color in aqueous solution.
o Nothing happens, so go back to the reaction equations:
I- + IO3- → I2
(this does not happen)
5 I- + IO3- + 6 H+ → 3 I2 + 3 H2O
(balanced equation)
Add a few drops of 6 M H2SO4 and shake. You will see an orange color appear as I2 is produced.
Add 50 mL hexane, shake, and vent. Two layers appear, an orange aqueous layer, and a pink organic
layer, as I2 dissolves readily in hexane.
Clean-Up
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Pour all solutions into the organic waste container.
Revised Spring 2015
AMM
Presentation
• Pour the KI (aq) and KIO3 (aq) into the separatory funnel and
shake to mix.
o We expect I- to reduce the IO2- ion to I2, which would yield an
orange color in aqueous solution.
o Nothing happens, so go back to the reaction equations:
I- + IO3- → I2
5 I- + IO3- + 6 H+ → 3 I2 + 3 H2O
(this does not happen)
(balanced equation)
• Add a few drops of 6 M H2SO4 and shake. You will see an
orange color appear as I2 is produced.
• Add 50 mL hexane, shake, and vent. Two layers appear, an
orange aqueous layer, and a pink organic layer, as I2 dissolves
readily in hexane.
Revised Spring 2015
AMM