Dichromate ions Breathalyzer test

The reaction of alcohol with orange dichromate ions to produce blue-green chromium(III) ions is used in the Breathalyzer test, a test that measures the presence of alcohol in a person s breath. How could a colorimeter be used in this analysis ... 

In the Breathalyzer test, the subject blows into a tube connected to a vial. The exhaled air collects in the vial, which already contains a mixture of sulfuric acid, potassium dichromate, water, and the catalyst silver nitrate. The alcohol reacts with the dichromate ion in the following redox reaction. 

One type of breathalyzer detects whether ethanol is in the breath of a person. Ethanol is oxidized to acetaldehyde by dichromate ions in acidic solution. The dichromate ion in solution is orange, while the Cr + aqueous ion is green. The appearance of a green color in the breathalyzer test shows that the breath exceeds the legal limit of alcohol. The equation is... 

Organic alcohols react with orange dichromate ions, producing blue-green chromium(lll) ions. This reaction is used in a Breathalyzer test to test for the presence of alcohol in a person s breath. In this MiniLab, you win use this reaction to test for the presence of alcohol in a number of household hygiene, cosmetic, and cleaning products. 

The Human Perspective Alcohol Consumption and the Breathalyzer Test (Chapter 13), describes the reaction between the dichromate ion and ethanol to produce acetic acid. How much acetic acid can be produced from a mixture containing excess of dichromate ion and 1.00 X 10 g of ethanol ... 

If the person fails this test—determined by the extent to which the green color spreads through the tube—a more accurate Breathalyzer test is administered. The Breathalyzer test also depends on the oxidation of breath ethanol by sodium dichromate, but it provides more accurate results because it is quantitative. In the test, a known volume of breath is bubbled through an acidic solution of sodium dichromate, and the concentration of chromic ion is measured precisely with a spectrophotometer. 

A chemical "breathalyzer" test works because ethanol in the breath is oxidized by the dichromate ion (orange) to form acetic acid and chromium(lll) ion (green). The balanced reaction is... 

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