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Nitrogen dioxide, NO₂, and dinitrogen tetroxide, N₂O₄, form an equilibrium mixture represented by the following equation - VCE - SSCE Chemistry - Question 19 - 2020 - Paper 1
Question 19
Nitrogen dioxide, NO₂, and dinitrogen tetroxide, N₂O₄, form an equilibrium mixture represented by the following equation. 2NO₂(g) ⇌ N₂O₄(g) ΔH = -57.2 kJ mol⁻¹ A ... show full transcript
Worked Solution & Example Answer:Nitrogen dioxide, NO₂, and dinitrogen tetroxide, N₂O₄, form an equilibrium mixture represented by the following equation - VCE - SSCE Chemistry - Question 19 - 2020 - Paper 1
Step 1
Which one of the following describes the change that was made to the initial equilibrium system and the color change that occurred between t₁ and t₂?
Answer
According to Le Chatelier's principle, an increase in temperature for an exothermic reaction (as indicated by the negative ΔH) will shift the equilibrium position to favor the reactants, in this case, NO₂, which is brown. Consequently, the solution becomes darker as the concentration of NO₂ increases, indicating that the temperature must have been increased and the color darkened. Thus, the correct answer is B: The temperature was increased and the colour darkened.