The reaction that occurs in a breath analyser, a device used to determine the alcohol level in a person's blood stream is \(2 \mathrm{~K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}+8 \mathrm{H}_{2} \mathrm{SO}_{4}+3 \mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O} \longrightarrow 2 \mathrm{Cr}_{2}\left(\mathrm{SO}_{4}\right)_{3}+3 \mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}+2 \mathrm{~K}_{2} \mathrm{SO}_{4}+11 \mathrm{H}_{2} \mathrm{O}\) If the rate of appearance of \(\mathrm{Cr}_{2}\left(\mathrm{SO}_{4}\right)_{3}\) is \(2.67 \mathrm{~mol} \mathrm{~min}^{-1}\) at a particular time, the rate of disappearance of \(\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O}\) at the same time is \_\_\_\_ \(\mathrm{mol} \mathrm{min}^{-1}\). (Nearest integer)

JEE Main · 2021 · 27 Aug 2021 · Shift 1 · Chemical Kinetics

The reaction that occurs in a breath analyser, a device used to determine the alcohol level in a person's blood stream is

2 K_{2} Cr_{2} O_{7} + 8 H_{2} SO_{4} + 3 C_{2} H_{6} O ⟶ 2 Cr_{2} (SO_{4})_{3} + 3 C_{2} H_{4} O_{2} + 2 K_{2} SO_{4} + 11 H_{2} O

If the rate of appearance of

Cr_{2} (SO_{4})_{3}

2.67 mol min^{- 1}

at a particular time, the rate of disappearance of

C_{2} H_{6} O

at the same time is ____

mol min^{- 1}

. (Nearest integer)

Answer: 4

The balanced equation links the rates by

- \frac{1}{3} \frac{d [ C _{2} H _{6} O ]}{d t} = \frac{1}{2} \frac{d [ C r _{2} ( S O _{4} ) _{3} ]}{d t}

. With the rate of appearance of

C r_{2} (S O_{4})_{3}

equal to

2.67 mol mi n^{- 1}

, the rate of disappearance of

C_{2} H_{6} O

\frac{3}{2} \times 2.67 = 4.005 \approx 4 mol mi n^{- 1}

JEE Main · 2021 · 27 Aug 2021 · Shift 1 · Integer answer