Chemistry · Thermodynamics & Thermochemistry

JEE Advanced 2023 — Paper 1 — Question 42

In a one-litre flask, 6 moles of A undergoes the reaction A(g)⇌P\mathrm{A}(\mathrm{g}) \rightleftharpoons \mathrm{P} (g). The progress of product formation at two temperatures (in Kelvin), T1\mathrm{T}_{1} and T2\mathrm{T}_{2}, is shown in the figure: If T1=2T2T_{1}=2 T_{2} and (ΔG2θ−ΔG1θ)=RT2ln⁡x\left(\Delta G_{2}^{\theta}-\Delta G_{1}^{\theta}\right)=R T_{2} \ln x, then the value of xx is ….\ldots .. [ [ΔG1θ\left[\Delta G_{1}^{\theta}\right. and ΔG2θ\Delta G_{2}^{\theta} are standard Gibb's free energy change for the reaction at temperatures T1T_{1} and T2T_{2}, respectively.]

Question figure

Answer: 8

Numerical answer — enter this value.

Step-by-step solution

A(g)⇌P(g)A(g) \rightleftharpoons P(g)

Initial mole60Initial\ mole \qquad 6 \qquad 0

at eq. at T124(Keq)T1=42=2at\ eq.\ at\ T_1 \qquad 2 \qquad 4 \qquad (K_{eq})_{T_1} = \frac{4}{2} = 2

at eq. T242(Keq)T2=24=12at\ eq.\ T_2 \qquad 4 \qquad 2 \qquad (K_{eq})_{T_2} = \frac{2}{4} = \frac{1}{2}

\Delta G_1^\circ &= -RT_1 \ln 2 \\ \Delta G_2^\circ &= -RT_2 \ln \frac{1}{2} = RT_2 \ln 2 \\ \Delta G_2^\circ - \Delta G_1^\circ &= RT_2 \ln 2 + RT_1 \ln 2 \quad \therefore T_1 = 2T_2 \\ \Delta G_2^\circ - \Delta G_1^\circ &= RT_2 \ln 2 + R(2T_2) \ln 2 \\ &= 3RT_2 \ln 2 = RT_2 \ln 2^3 \\ &= RT_2 \ln 8 \\ RT_2 \ln 8 &= RT_2 \ln X \\ \text{So, } X &= 8 \end{aligned}$$

Answer key and solution verified before publishing.

Practise Thermodynamics & Thermochemistry

Start with this question, then two more from the same chapter — with a tutor that explains every step. Free.

Exam
JEE Advanced 2023
Paper
Paper 1
Subject
Chemistry
Chapter
Thermodynamics & Thermochemistry
Topic
Gibbs Free Energy and the Third Law of Thermodynamics
In a one-litre flask, 6 moles of A undergoes the reaction A ( g )… | JEE Advanced 2023 PYQ with Solution · DhiX AI