Chemical equilibrium

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Question 2
Medium

Phosphorus pentachloride decomposes into phosphorus trichloride and chlorine according to the equilibrium below:

PCl5(g)⇌PCl3(g)+Cl2(g)ΔH=+124 kJ mol−1 \text{PCl}_5(\text{g}) \rightleftharpoons \text{PCl}_3(\text{g}) + \text{Cl}_2(\text{g}) \quad \Delta H = +124 \text{ kJ mol}^{-1} PCl5​(g)⇌PCl3​(g)+Cl2​(g)ΔH=+124 kJ mol−1

Both PCl5\text{PCl}_5PCl5​ and PCl3\text{PCl}_3PCl3​ are colourless gases, while Cl2\text{Cl}_2Cl2​ is a pale green-yellow gas.

Which statement(s) is/are correct?

  1. The forward reaction is accompanied by a positive entropy change.
  2. When the temperature of the equilibrium mixture is increased, the green-yellow colour darkens.
  3. The oxidation state of phosphorus decreases during the forward reaction.

1, 2 and 3

Only 1 and 2

Only 2 and 3

Only 1

Chemical equilibrium Questions

  1. A Level
  2. /Chemistry
  3. /Chemical equilibrium