Neco Model Questions Vol1 2020 Chemistry Question 50

Practice objective / multiple choice question 50 from the 2020 Neco Model Questions Vol1 Chemistry examination.

Neco Model Questions Vol1 2020 Chemistry Objective / Multiple Choice Hard Difficulty
Question 50 NECO_MODEL_QUESTIONS_VOL1 • 2020 • CHEMISTRY • objective

Consider the reduction of chromium(III) oxide by carbon at 1500 K: \(\mathrm{Cr_2O_3(s) + 3\,C(s) \rightarrow 2\,Cr(s) + 3\,CO(g)}\). The standard enthalpy and entropy changes for the reaction are ΔH° = +200 kJ mol⁻¹ and ΔS° = +0.20 kJ mol⁻¹ K⁻¹. (i) Calculate the equilibrium constant K at 1500 K. (ii) Determine the maximum partial pressure of CO that will still allow the reaction to proceed spontaneously (solids have unit activity). (iii) Comment on the feasibility of the process if the typical CO partial pressure in the furnace is 0.5 atm.

Answer Options

A. (i) K ≈ 3.0 × 10⁴, (ii) p_{CO}(max) ≈ 146 atm, (iii) Since the usual p_{CO} (0.5 atm) is well below the limit, the reduction is thermodynamically feasible in practice.
B. (i) K ≈ 3.0 × 10³, (ii) p_{CO}(max) ≈ 14.6 atm, (iii) Since the usual p_{CO} (0.5 atm) exceeds the limit, the reduction is not thermodynamically feasible.
C. (i) K ≈ 3.0 × 10⁻³, (ii) p_{CO}(max) ≈ 1.46 atm, (iii) Since the usual p_{CO} (0.5 atm) exceeds the limit, the reduction is not thermodynamically feasible.
Correct Answer D. (i) K ≈ 3.0 × 10³, (ii) p_{CO}(max) ≈ 14.6 atm, (iii) Since the usual p_{CO} (0.5 atm) is well below the limit, the reduction is thermodynamically feasible in practice.
Correct Answer
D
Correct Option:
(i) K ≈ 3.0 × 10³, (ii) p_{CO}(max) ≈ 14.6 atm, (iii) Since the usual p_{CO} (0.5 atm) is well below the limit, the reduction is thermodynamically feasible in practice.

About This Question

This is Neco Model Questions Vol1 2020 Chemistry Question 50. It is one of the objective questions from the 2020 Neco Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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