The reaction that occurs in a Breathalyzer, a device used to determine the alcohol level in a person's bloodstream, is given below. If the rate of appearance of Cr2(SO4)3 is 1.64 mol/min at a particular moment, what is the rate of disappearance of C2H6O at that moment? 2 K2Cr2O7 + 8 H2SO4 + 3 C2H6O ? 2 Cr2(SO4)3 + 2 K2SO4 + 11 H2O

2.46 mol /min

Explanation:

Let's consider the following redox reaction that takes place in a breathalyzer.

2 K₂Cr₂O₇ + 8 H₂SO₄ + 3 C₂H₆O → 2 Cr₂(SO₄)₃ + 2 K₂SO₄ + 11 H₂O

The molar ratio of C₂H₆O to Cr₂(SO₄)₃ is 3:2. We know that the rate of appearance of Cr₂(SO₄)₃ is 1.64 mol/min. We can find the rate of disappearance of C₂H₆O.

(1.64 mol Cr₂(SO₄)₃ / min) × (3 mol C₂H₆O/2 mol Cr₂(SO₄)₃) =

= 2.46 mol C₂H₆O/min