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CHM 101 CHM 101 Past Questions Objective Question
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Question

Each of the following equilibria is subjected to two changes carried out simultaneously: (i) the pressure is increased at constant temperature; (ii) the temperature is reduced at constant pressure. For which equilibrium will both of these changes result in a decrease in the proportion of the products?
Options
A H₂(g) + I₂(g) ⇌ 2HI(g); ΔH = +53 kJ mol⁻¹
B 4NH₃(g) + 5O₂(g) ⇌ 4NO(g) + 6H₂O(g); ΔH = -950 kJ mol⁻¹
C N₂(g) + 3H₂(g) ⇌ 2NH₃(g); ΔH = -92 kJ mol⁻¹
D N₂O₄(g) ⇌ 2NO₂(g); ΔH = +57 kJ mol⁻¹
Correct Answer
Correct Answer

Option D is the correct answer.

Detailed Explanation

For both changes to decrease products: (i) Increasing pressure favors side with fewer gas moles. (ii) Decreasing temperature favors exothermic direction (negative ΔH). For option D: N₂O₄ ⇌ 2NO₂, Δn = +1, so increased pressure favors reactants (decrease products). ΔH is positive (endothermic), so decreasing temperature favors reactants (decrease products). Both changes decrease products.

Hint

Apply Le Chatelier's principle: pressure affects gas moles; temperature affects heat direction.

Question Info

Course: CHM 101
Topic: CHM 101 Past Questions
Type: Objective
Difficulty: Not specified
Question 1170 of 1872
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