'One Cola and one Beer, please' - Modified Landolt Reaction

Demonstration Experiment on Video

'One Cola and one Beer, please'' - Modified Landolt Reaction

Objective: Reaction Rate

Peter Keusch

German version

Chemicals:
sodium disulfite
potassium iodate
iodic acid
ethanol
30% sulfuric acid
starch, soluble

Glass wares:

Coca Cola bottle 1.5 L
glass beer stein 1 L
measuring cylinder 500 mL
2 volumetric flasks 1000 mL
2 beakers 500 mL
3 beakers 50 mL
3 beakers 40 mL
1 graduated measuring pipet 10 mL
2 volumetric pipets 5 mL
2 volumetric pipets 30 mL
1 volumetric pipet 50 mL
4 pipette bulbs

Hazards and safety precautions:

Sodium disulfite may cause irritation and may be harmful if swallowed. May cause allergic reaction.skin and eye irritant.

Potassium iodate is harmful if swallowed. May be harmful by inhalation or through skin absorption. Irritant.

Iodic acid is harmful by ingestion. Corrosive - may cause burns to mouth and stomach if swallowed. Eye, skin and respiratory irritant.

Conc. sulfuric acid is highly toxic. Causes severe burns. May be fatal if swallowed. May cause cancer through inhalation. Very destructive of mucous membranes.

Ethanol is highly flammable.

Safety glasses and safety gloves must be worn. Suitable ventilation!

The following solutions are prepared in advance.

Coca Cola:

Solution A: 0.5 g of starch are dissolved in a 50 mL beaker containing 50 mL of boiling water.

Solution B: 2.5 g iodic acid are dissolved in a 50 mL beaker containing 50 mL of deionized water.

Solution C: 0.85 g sodium disulfite are dissolved in a 50 mL beaker containing 50 mL of deionized water.

Beer:

Solution D: 2.15 g potassium iodate are dissolved in a 1000 mL volumetric flask containing 1 L of deionized water.

Solution E: 0.48 g sodium disulfite are dissolved in a 1000 mL volumetric flask containing 1 L of deionized water. 5 mL of ethanol and 9 mL of 30% sulfuric acid are added to the disulfite solution.

Experimental procedure:

CocaCola:

The Coca Cola bottle is filled with 1410 mL deionized water. 15 mL of solution A, 30 mL of solution B and 30 mL of solution are added. The bottle cap is closed and the bottle is shaken.

Beer:

Using 500 mL beakers equal volumes (500 mL) of solution D and solution E are poured simultaneously into a beer mug, containing 20 mL of a washingup liquid.

Results:

Videoclip (Download RealPlayer .rm file)

Discussion:
Landolt Reaction - Iodine clock Kinetics

References:
Demonstration Experiment on Video Cocktail 'Old Nassau' - Modified Landolt Reaction

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