For the synthesis of sulfur trioxide, 2 SO (g) + O (g) ⇌ 2 SO (g)
CHEMISTRY · Multi-part · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)
Problem
For the synthesis of sulfur trioxide,
2 SO2(g) + O2(g) ⇌ 2 SO3(g),
three students propose the following equilibrium‐constant expressions:
(a) Write the correct equilibrium‐constant expression Kc for the reaction.
(b) For each proposed expression (I–III), state whether it is correct or incorrect. For every incorrect expression, identify the specific stoichiometric or conceptual error that leads to the deviation from your answer in part (a).
(c) Rewrite one of the incorrect expressions so that it becomes correct without simply restating your answer from part (a); explain the modification briefly.