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JAMB Chemistry 1985 Question 22

Question 22

Chemical Equilibrium

A certain industrial process is represented by the chemical equation 2A(g) + B(g) ⇌ C(g) + 3D(g) ΔH = X kJ mol−1. Which of the following conditions will favour the yield of the products?

  1. A.increase in temperature, decrease in pressure
  2. B.increase in temperature, increase in pressure
  3. C.decrease in temperature, increase in pressure
  4. D.decrease in temperature, decrease in pressure
  5. E.constant temperature, increase in pressure.
Show the answer and explanation

Answer: A (increase in temperature, decrease in pressure)

Explanation

The products side has more gas molecules (4 against 3), so a lower pressure shifts the equilibrium to the right. Taking ΔH = +X (endothermic), a higher temperature also shifts it to the right.