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How Breathalyzer Determines Alcohol Level In Body

Ogunshola Seyi

Breathalyzer Or Drunkometer

Breathalyzer is a portmanteau of breath and analyzer. A device used to determine if a suspect is drunk or not. Alcohol related vehicle accidents, on Nigerian roads kill not less than 20,000 and injure millions of people each year. Nigerian government need to prohibit any person with a blood alcohol level of equal to or greater than 1.0g/l from driving a vehicle on Nigerian roads. The breathalyzer or drunkometer works on the principle of redox reaction that is Reduction and oxidation reaction. It is a device we can design, construct and commercialize with sixth form chemistry. The type elucidated here is the use and dispose version, the Nigerian police should be interested in this idea and help boost the idea of backward integration or Nigerian content. The diagram of the device is shown below:


To help determine the amount of alcohol in the body, breathalyzer or drunkometer receive a breath sample for 15 seconds and measure its alcohol content by means of redox reaction leading to a colour change from yellow or orange to green at acidic condition and a suitable catalyst. Alcohol vapour in the subject’s breath reacted with the yellow crystals of potassium dichromate and the colour change happens as explained in the foregoing. If the green colour stain extend beyond the red line drawn on the tube then the subject failed the test and he is therefore liable.

The reaction can be summed up as: C2H5OH(aq) + Cr2O72-(aq) CO2 (g) + Cr3+(aq) C2H5OH is oxidized (oxidation number of carbon (C) increase from -2 +4; Oxidation number of Cr2O72- is reduced from + 6 +3. The balanced half equations are: Oxidation: C2H5OH(aq) + 3H2O 2CO2(g) + 12H+(aq) + 12e- Reduction: Cr2O72-(aq) + 14H+(aq) + 6e- 2Cr3+(aq)+ 7H2O Multiply the reduction half – equation by 2 and adding it to the oxidation half – equation, after simplification gives. C2H5OH(aq) +2Cr2O72-(aq) + 16H+(aq) 2CO2(g) + 4Cr3+(aq) + 11H2O The level of alcohol in the blood can be determined by titrating blood plasma with potassium dichromate (vi) according to the unbalanced equation below. H+(aq) + Cr2O72-(aq) + C2H5OH(aq) Cr3+(aq) + CO2(g) + H2O

If you are interested in the development of this idea you can reach out to me through my contact. DO YOU KNOW? If your eyes tear when you peel onions, this molecule (Allyl Sulfide) is the culprit It is water soluble, so cut and onions under water, no tears! Other ways of avoiding the tears are: – You can use a sharp knife to cut the onion to reduce the amount of damage to the onion cells. – Cool the onion in a refrigerator to suppress the scattering of the lachrymator . – Wearing swimming goggles or ski goggles while cutting the onion. – Use a ventilator or fan to blow the allyl sulfide away. Addendum Knowledge Will Forever Govern Ignorance, A People Who Wish To Be Their Own Governor, Must Arm Themselves With The Power Which Knowledge Gives.- James Madison Number 4.

Thanks And God Bless.

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