How to Facilitate a Chemical Reaction According to Le Chatelier’s Principle – Part 1

Chemical equilibrium is the state in which both the reactants and products in a chemical reaction are present in concentrations that have no more propensity to change with time, s.t. there is no visible alteration in the system properties.


This state results when the forward reaction proceeds at the same rate as the reverse/backward reaction, and is known as dynamic equilibrium.

Le Chatelier's principle (aka Chatelier's principle, Braun–Le Chatelier principle, Le Chatelier–Braun principle or the equilibrium law) states if a system in a chemical equilibrium is subjected to a change in conditions, viz., concentration, temperature or pressure, the equilibrium shifts in such a way that the effect of change is nullified.

Question:

How would you favor the forward reaction for the following?

PCl5(g) ⇌ PCl3(g) + Cl2(g); ΔH >0

Solution:



Click to enlarge the image

Qp = Reaction quotient, Kp = Equilibrium constant in terms of partial pressure, Δng = Change in moles of gaseous molecules

NOTE: Adding an inert gas to a reaction at equilibrium at constant volume has no effect on the position of the equilibrium. While the total pressure of the system goes up, the concentrations (moles/volume) and partial pressures of the reactants and products remain the same.

Luminous Le Chatelier's principle❓ Let Chemaficionado know at mychemistryhomework@gmail.com❗

References:

(1)    Wikipedia Contributors. Chemical equilibrium. Wikipedia. https://en.wikipedia.org/wiki/Chemical_equilibrium.

(2)    Wikipedia Contributors. Le Chatelier’s principle. Wikipedia. https://en.wikipedia.org/wiki/Le_Chatelier%27s_principle.

(3)    Ncert. Chemistry : Textbook for Class XI - Part.I; National Council Of Educational Research And Training: New Delhi.

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