To measure alcohol, a suspect breathes into the device. The breath sample is bubbled in one vial
through a mixture of sulfuric acid, potassium dichromate, silver nitrate and water. The silver nitrate
is a Catalyst, a substance that makes a reaction go faster without participating in it. The sulfuric
acid, in addition to removing the alcohol from the air, also might provide the acidic condition
needed for this reaction. Alcohol that a person drinks shows up in the breath because it gets
absorbed from the mouth, throat, stomach and intestines into the bloodstream.