Do you know how the police detect whether suspected drivers have consumed alcohol or not?

CBSE Class 10 CBSE Class 10 Science
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  1. The police officer asks the suspect to blow air into a plastic bag through a mouth piece of the detecting instrument which contains crystals of potassium- di-chromate .
  2. As potassium- di-chromate is a good oxidizing agent, it oxidizes any ethanol in the driver’s breath to ethanal and ethanoic acid.
  3. Orange $Cr _{ 2 }$$O _{ 7 }$ changes to bluish green ${{Cr}^{3+}}$ during the process of the oxidation of alcohol.
  4. The length of the tube that turned into green is the measure of the quantity of alcohol that had been drunk.
  5. The police even use the IR Spectra to detect the bonds C - OH and C - H of
    $CH _{ 3 }$ - $CH _{2 }$OH.