Question

The reaction $:A_{(g)}+2B_{(g)}\to C_{(g)}+D_{(g)}$ is an elementary process. In an experiment, the initial partial pressure of $A$ and $B$ are $P_A=0.60atm$ and $P_B=0.80atm.$ When $P_C=0.20$ atm, the rate of reaction relative to the initial rate is:

• A. $\frac{1}{16}$
• B. $\frac{1}{24}$
• C. $\frac{1}{6}$
• D. $\frac{1}{48}$

Answer 1

Answer: (C)

Since it is an elementary reaction

Rate of reaction $=K(A)(B{)}^2$

Rate of reaction (initial) $=K[0.60][0.80{]}^2...(1)$

Rate of reaction (final) $=K[0.40][0.40{]}^2...(2)$

$\frac{{\text{ Rate }}_{\text{final }}}{{\text{ Rate }}_{\text{initial }}}=\frac{(0.40)(0.40{)}^2}{(0.6)(0.8{)}^2}$

$=\frac{1}{6}$