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QJEEM25Chdd23: JEE Main 2025 Chemistry - Class 12 JEEM25Chdd23 Solution: For the thermal decomposition of at constant volume, the…

For the thermal decomposition of N2O5( g)\mathrm{N}_2 \mathrm{O}_5(\mathrm{~g}) at constant volume, the following table can be formed, for the reaction mentioned below.

2 N2O5( g)→2 N2O4( g)+O2( g)2 \mathrm{~N}_2 \mathrm{O}_5(\mathrm{~g}) \rightarrow 2 \mathrm{~N}_2 \mathrm{O}_4(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g})

Sr. No. Time/s Total pressure/(atm)
1 0 0.6
2 100 ' x\mathrm{x} '

x=\mathrm{x}= __________ ×10−3 atm\times 10^{-3} \mathrm{~atm} [nearest integer]

Given : Rate constant for the reaction is 4.606×10−2 s−14.606 \times 10^{-2} \mathrm{~s}^{-1} .

Step-by-Step Verified Solution

amp;KN2O5=2×4.606×10−2 S−1amp;2 N2O5( g)⟶2 N2O4( g)+O2( g)\begin{aligned}& \mathrm{K}_{\mathrm{N}_2 \mathrm{O}_5}=2 \times 4.606 \times 10^{-2} \mathrm{~S}^{-1} \\& 2 \mathrm{~N}_2 \mathrm{O}_5(\mathrm{~g}) \longrightarrow 2 \mathrm{~N}_2 \mathrm{O}_4(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g})\end{aligned}

Pi0.600Pf0.6−PPP2

amp;2×4.606×10−2=2.303100log⁡0.60.6−Pamp;4log⁡100.60.6−Pamp;104=0.60.6−Pamp;⇒0.6×104−104P=0.6\begin{aligned}& 2 \times 4.606 \times 10^{-2}=\frac{2.303}{100} \log \frac{0.6}{0.6-\mathrm{P}} \\& \quad 4 \log _{10} \frac{0.6}{0.6-\mathrm{P}} \\& \quad 10^4=\frac{0.6}{0.6-\mathrm{P}} \\& \Rightarrow 0.6 \times 10^4-10^4 \mathrm{P}=0.6\end{aligned}

amp;⇒104P=0.6(104−1)amp;P=(6000−0.6)×10−4amp;=5999.×10−4amp;=0.59994amp;PTotal =0.6+P2amp;=0.6+0.29997amp;=0.89997amp;=899.97×10−3amp; Ans. 900\begin{aligned}\begin{aligned}& \Rightarrow 10^4 \mathrm{P}=0.6\left(10^4-1\right) \\& \mathrm{P}=(6000-0.6) \times 10^{-4} \\&=5999 . \times 10^{-4} \\&=0.59994 \\& \mathrm{P}_{\text {Total }}=0.6+\frac{\mathrm{P}}{2} \\&= 0.6+0.29997 \\&= 0.89997 \\&=899.97 \times 10^{-3} \\& \text { Ans. } 900\end{aligned}\end{aligned}

JEE Main 2025 (Online) 23rd January Morning Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 6 English Explanation

PTotal =0.6+x2\mathrm{P}_{\text {Total }}=0.6+\frac{\mathrm{x}}{2}

As given in equation

Kr=4.606×10−2sec−1\mathrm{K}_{\mathrm{r}}=4.606 \times 10^{-2} \mathrm{sec}^{-1}

(Here language conflict in question)

( Kr=KA2\mathrm{K}_{\mathrm{r}}=\frac{\mathrm{KA}}{2} not considered)

Krtamp;=ln⁡0.60.6−x4.606amp;×10−2×100=2.303log⁡0.60.6−xPTotal amp;=0.6+0.5942=0.897 atmamp;=897×10−3 atm\begin{aligned}\mathrm{K}_{\mathrm{r}} \mathrm{t} & =\ln \frac{0.6}{0.6-\mathrm{x}} \\4.606 & \times 10^{-2} \times 100=2.303 \log \frac{0.6}{0.6-\mathrm{x}} \\\mathrm{P}_{\text {Total }} & =0.6+\frac{0.594}{2}=0.897 \mathrm{~atm} \\\quad & =897 \times 10^{-3} \mathrm{~atm}\end{aligned}

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