Question

Consider the following gaseous reaction where initial pressure of $A ( g )$ is $200$ torr $A ( g ) \rightarrow 3 B ( g )+ C ( g )$ After time t, the pressure of system increased to $650$ torr. Calculate the value of $t$ (in seconds) (Given: rate constant of reaction, $k =4.606\times 10^{-3} \sec ^{-1}, \log 2=0.3$ )

• A. 600
• B. 300
• C. 50
• D. 5

Answer 1

Answer: (B)

$A(g) \longrightarrow 3 B(g)+C(g)$
at $t=0\,\, 200$ torr $\,\,-\,\,-$
at $t=t\,\, 200-p\,\, 3 p\,\, p$
$200-p+3 p+ p=650 $
$p=150$ torr
$t=\frac{1}{k} \times 2.303 \times \log \frac{200}{200-p}$
$=\frac{1 \times 2.303 \times \log 4}{4.606 \times 10^{-3}}=300\, \sec$