Breathalyzers measure the alcohol (ethanol, C2H6O) content in an exhaled breath using a redox reaction. The C2H6O reacts with an acidic solution of potassium dichromate, forming acetic acid. The color of the solution changesbecause some of the orange chromate is converted to the green Cr3+, and the Breathalyzer measures this color change.C2H6O + Cr2O7 = C2H4O2 + Cr3+ (UNBALANCED)(a) Which reactant is oxidized? Which reactant is reduced?Which reactant is the oxidizing agent? Which reactant is the reducing agent?(b) Balance the redox reaction above that occurs in a Breathalyzer. Note the reaction occurs in acidic conditions.(c) What is E° for the reaction if the standard reduction potential for the acetic acid / ethanol half-reaction is 0.058 V?(Note: see Appendix L in the OpenStax textbook for the reduction potential of the other half-reaction)
Breathalyzers measure the alcohol (ethanol, C2H6O) content in an exhaled breath using a
because some of the orange chromate is converted to the green Cr3+, and the Breathalyzer measures this color change.
C2H6O + Cr2O7 = C2H4O2 + Cr3+ (UNBALANCED)
(a) Which reactant is oxidized? Which reactant is reduced?
Which reactant is the oxidizing agent? Which reactant is the reducing agent?
(b)
(c) What is E° for the reaction if the standard reduction potential for the acetic acid / ethanol half-reaction is 0.058 V?
(Note: see Appendix L in the OpenStax textbook for the reduction potential of the other half-reaction)
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