Question

The reaction $A\left(g\right)+2B\left(g\right)\to C\left(g\right)+D\left(g\right)$ is an elementary process. In an experiment, the initial partial pressure of A and B are $P_A=0.60$ and $P_B=0.80$ atm. When $P_C=0.2$ atm, the rate of reaction relative to the initial rate is:

• A. $1/48$
• B. $1/24$
• C. $9/16$
• D. $1/6$

Answer 1

The correct option is D $1/6$

$r_1=k\left[A\right][B{]}^2=k[0.6\left]\right[0.80{]}^2$
After the reaction,
$\begin{array}{ccccccc}A& +& 2B& \to & C& +& D\\ 0.6-0.2& & 0.8-0.4& & 0.2& & 0.2\\ 0.4& & 0.4& & 0.2& & 0.2\end{array}$
Now,
$\frac{r_2}{r_1}=\frac{k\left(0.4\right)(0.4{)}^2}{k\left(0.6\right)(0.8{)}^2}=\frac{1}{6}$