The breath test conducted by police to check drunken driver has which one of the following on the filter paper?
- APotassium dichromate-sulfuric acid
- BPotassium permanganate-sulfuric acid
- CSilica gel coated with silver nitrate
- DTurmeric
- ENone of the above / More than one of the above
Show answer and explanation
Correct answer: (a) Potassium dichromate-sulfuric acid
Explanation
The police breathalyser detects alcohol exhaled from the lungs after it dissolves in the bloodstream.
The filter paper carries potassium dichromate–sulfuric acid, where orange Cr₂O₇²⁻ (Cr⁶⁺) oxidises ethanol and turns green Cr³⁺.
The extent of this colour change indicates the blood alcohol concentration.