Chemistry · Chemical Kinetics

JEE Main 2024 — 5 April, Shift 2 — Question 85

Consider the following single step reaction in gas phase at constant temperature.

$2 \mathrm{~A}_{(\mathrm{g})}+\mathrm{B}_{(\mathrm{g})} \rightarrow \mathrm{C}_{(\mathrm{g})}$

The initial rate of the reaction is recorded as $r_{1}$ when the reaction starts with 1.5 atm pressure of A and 0.7 atm pressure of B. After some time, the rate $r_{2}$ is recorded when the pressure of $C$ becomes 0.5 atm. The ratio $r_{1}: r_{2}$ is $\qquad$ $\times 10^{-1}$ . (Nearest integer)

Answer: 315

Numerical answer — enter this value.

Step-by-step solution

$2 \mathrm{~A}(\mathrm{~g})+\mathrm{B}(\mathrm{g}) \longrightarrow \mathrm{C}(\mathrm{g})$

$\mathrm{r}_{1} \quad 1.5 \mathrm{~atm} \quad 0.7 \mathrm{~atm}$

$\because\mathrm{r}=\mathrm{K}\left[\mathrm{P}_{\mathrm{A}}\right]^{2}\left[\mathrm{P}_{\mathrm{B}}\right]$ $\mathrm{r}_{1}=\mathrm{K}[1.5]^{2}[0.7]$

$\mathrm{r}_{2}=\mathrm{K}[0.5]^{2}[0.2]$

$\frac{r_{1}}{r_{2}}=9 \times \frac{7}{2}=31.5=315 \times 10^{-1}$ Ans. 315

Answer key and solution verified before publishing.

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Exam: JEE Main 2024
Paper: 5 April, Shift 2
Subject: Chemistry
Chapter: Chemical Kinetics
Topic: Rate Laws and Rate Constant