why dichromate ions are used as breath analyzer?????????\
When the user exhales into a breath analyzer, any ethanol present in their breath is oxidized to acetic acid at the anode:
CH3CH2OH(g) + H2O(l) → CH3CO2H(l) + 4H+(aq) + 4e-
At the cathode, atmospheric oxygen is reduced:
O2(g) + 4H+(aq) + 4e- → 2H2O(l)
The overall reaction is the oxidation of ethanol to acetic acid and water.
CH3CH2OH(l) + O2(g) → CH3COOH(l) + H2O(l)
The electrical current produced by this reaction is measured by a microprocessor, and displayed as an approximation of overall blood alcohol content