Chemical Kinetics - Result Question 58
58. $2 X(g) \longrightarrow 3 Y(g)+2 Z(g)$
| Time (in min) |
0 | 100 | 200 |
|---|---|---|---|
| Partial pressure of $\boldsymbol{X}$ (in mm of $Hg$ ) |
800 | 400 | 200 |
Assuming ideal gas condition. Calculate
(a) order of reaction
(b) rate constant
(c) time taken for $75 \%$ completion of reaction
(d) total pressure when $p _x=700 $ $mm$
$(2005,4 M)$
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Answer:
Correct Answer: 58. $(950 $ $mm$ $ Hg)$
Solution:
- (a) Partial pressure becomes half of initial in every $100$ $ min$, therefore, order $=1$.
(b) $k \times 100=\ln \frac{800}{400}=\ln 2 \Rightarrow k=6.93 \times 10^{-3} $ $min^{-1}$
(c) For $75 \%$ reaction; time required $=2 \times$ half-life $=200$ $ min$
(d)
$\begin{aligned} & 2 X(g) \longrightarrow 3 Y(g)+2 Z(g) \\ & 800-x \quad \quad \frac{3}{2} x \quad \quad x \\ & \end{aligned}$
$ \begin{aligned} & \text { Total pressure }=800+\frac{3}{2} x \\ & \text { Also } 800-x=700 \Rightarrow x=100 \\ & \Rightarrow \text { Total pressure }=800+\frac{3}{2} \times 100=950 mm Hg \end{aligned} $
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