Chemistry - Chemical Kinetics Question with Solution | TestHub

(a) Let the initial pressure of A be $P_0$ mm of Hg, and the pressure of A decreased in 10 minutes be $a$.

A(g) $⟶$ 2B(g) + C(g)

Initially $P_0$ 0 0

At time $t=10$ min: $P_0-a$ $2a$ $a$

At $t=\infty$: 0 $2P_0$ $P_0$

After a long time interval, $P_{\infty }=2P_0+P_0=3P_0$.

$P_0=\frac{P_{\infty }}{3}=\frac{270}{3}=90\mathrm{mm}\circ fHg$

(b) For a first-order reaction, the rate constant expression is:

$k=\frac{2.303}{t}\log \frac{P_0}{P_0-a}$

Since$(P_0-a)+2a+a=176$.

$90+2a=176$. ∴ $a=43$.

$k=\frac{2.303}{10}\log \frac{P_0}{P_0-a}$

Since,

$P_0$-a+2a+a=176

90+2a=176 ∴ a = 43

$k=\frac{2.303}{10}\log \frac{90}{47}$

$=0.0650mi{n}^{-1}$

$k=650\times 10^{-4}mi{n}^{-1}$