Answer to Question #144018 in General Chemistry for gia

Question

Consider the following equilibrium process:
2I(g)<-->I2(g)
Predict the direction of the shift in equilibrium
when (a) a catalyst is added to the reaction
mixture, (b) the total pressure on the system is
increased, (c) adding gaseous I2 to the reaction
mixture, (d) the temperature is raised and (e)
adding He to the reaction mixture.

Answer 1

The equilibrium reaction is,

2I(g)<-->I₂(g)

a). When catalyst is added to the system it decreases the activation energy of the both forward and backward reaction so that's why it does not shift the position of equilibrium.

b). on increasing the pressure of the system the equilibrium will shift towards the left side.

The equilibrium constant can be expressed for this above reaction as,

K_eq = P_I2/(P_I)²

K_eq = [X_I2/(X_I)²]×[P_tot/Σn]^–1

K_eq = [n_I2/(n_I)²]×[Σn/P_tot]_____[1]

Where, X_i = mole fraction of the species involve in reaction

n_i = number of moles of species involve in reaction.

Σn = total number of moles in equilibrium

P_tot = total pressure of the system

so, according to the equation [1] on increasing the pressure of the system at equilibrium the, [Σn/P_tot] part of equilibrium constant will decreases that means to maintain the equilibrium the [n_I2/(n_I)²] part of equilibrium constant will increase. So, the equilibrium shift towards the right side.

c). On adding product, I₂ in the system the equilibrium with shift towards the left side according to the Le-Chatelier's principal.

d). As dimerization reaction heat will be liberated in this reaction.

On increasing the temperature of the reaction system the equilibrium will shift towards the left side (reactant) side of the equilibrium following Le-Chatelier's principal.

e). On adding noble gas to the reaction system at equilibrium the total number of moles in the equilibrium will increases.

K_eq = [n_I2/(n_I)²]×[Σn/P_tot]_______[1]

so, according to the equation [1] on increasing the number of moles, Σn of the system at equilibrium the, [Σn/P_tot] part of equilibrium constant will inecreases that means to maintain the equilibrium the [n_I2/(n_I)²] part of equilibrium constant will decrease. So, the equilibrium shift towards the left side.