Question

Determine the rate law for first order reaction 2A → R at constant pressure with 60% A in the initial reaction mixture and reduces by 15% in 4 minutes.

(a) -rA = 0.17 CA

(b) -rA = CA

(c) -rA = 2CA

(d) -rA = 3.6CA

I had been asked this question in an online quiz.

My doubt stems from Batch Reactor Design Equations in division Ideal Reactors for a Single Reaction, Conversion and Reactor Sizing of Chemical Reaction Engineering

Answer 1

The correct option is (a) -rA = 0.17 CA

For explanation I would say: 2A → R

εA = \(\frac{.7-1}{1}\) = -0.3

\(\begin{array}{c|c c}

  & X_A=0 & X_A = 1 \\

\hline

 A & 0.6 & 0.3 \\

 I & 0.4 & 0.4 \\

\hline

 & 1 & 0.7 \\

\end{array}

\)

ΔV = V-Vo

       = Vo – 0.15 VO – VO = -0.15 VO

-ln(1-\(\frac{ΔV}{Vo εA}\)) = kt

=> k = 0.173 min^-1.