Look at the the instruction (2) Essay Example | Topics and Well Written Essays - 750 words

Look at the the instruction (2) - Essay Example In solution, ethanol reacts with the potassium dichromate, reducing the dichromate ion to chromium(III) ion. This reduction results in a change of the solution’s color from red orange to green. The extent of the color change, precisely measured by photoelectric cells revealed the amount of alcohol in the sample (Willet, 1996). This chemical analysis though, is not very accurate due to the presence of interfering compounds which are similar in structure with alcohol. Since potassium dichromate is a strong oxidizer, numerous alcohol groups can be oxidized by it, thereby producing false positive results. New models include breathe analyzers using the fuel cell and infrared technologies. In a fuel cell, two electrodes are immersed in an electrolyte – a substance that conducts electricity. Fuel, typically hydrogen, is provided to one electrode, and oxygen to the other. The result is a flow of electricity between the electrodes . In a breathe analyzer, the alcohol in the breathe becomes the fuel for the fuel cell, the higher the concentration of alcohol in the breathe, the more electricity is generated. The measure of the strength of the current being generated will determine the concentration of alcohol in the breathe sample (Willet, 1996). The fuel cell technology may be considered as chemical sensor even if it is the electricity generated that is being measured. The electricity generated is proportional to the amount of fuel supplied by the alcohol group to the fuel cell. This means that the electricity generated is dependent on the fuel or the amount of alcohol supplied. The limiting factor or the sensor is the alcohol compound in the breathe sample. When the alcohol in the breathe sample is already exhausted, generation of electricity will also stop. Thus, the alcohol from the breathe sample is considered as the chemical sensor since the electricity generated is