For the equilibrium system below, which of the following would decrease the concentration of 𝑃𝐶𝑙3(𝑔)?

Question

𝑃𝐶𝑙3(𝑔) + 𝐶𝑙2(𝑔) ↔ 𝑃𝐶𝑙5(𝑔) + 45𝑘𝐽

a. Increased temperature

b. Decreased pressure

c. Increased [𝑃𝐶𝑙5]

d. Increased [𝐶𝑙2]

Answer 1

Adding Cl2 would increase the stress on the reactant side as an excess to the equilibrium. To relieve the stress the reaction would shift to the right decreasing PCl3 which would be reacting with the excess Cl2 until a new equilibrium is established.

Increasing the temperature, decreasing pressure or increasing PCl5 places the stress factors on the product side causing the reaction to shift left to relieve the stress and PCl3 would increase.

'D' choice is the best answer. Hope this helps.

Answer 2

You may also wish to see my post on the question from 'Urgent' at 7:02. Just before your post. Same kind of question. Ya'll must be in the same class.