Question

Consider LeChatelier’s principle. Explain how the equilibrium of a gas phase reaction will generally shift when the partial pressure (or concentration) of each gaseous reactant and product is increased proportionally. Determine which way the equilibrium will shift for the HI reaction if it is at equilibrium and then all three partial pressures are doubled.

Answer 1

according LeChatelier’s principle the pressure of the system increases. the equilibrium will shift to where decrease in number of moles side and pressure has no effect on equilibrium position when reactatns moles equal to product moles

example :

1) N2 (g)+ 3H2 (g) <-----------------> 2NH3(g)

reactant moles = 4 , product moles = 2

on increasing pressure reaction shifts to the product side

2) 2 SO3 (g) <-----------------> 2 SO2(g) + O2 (g)

reactant moles = 2 , product moles = 3

on increasing pressure reaction shifts to the reactant side

3) N2 (g) + O2 (g) <-------------> 2NO(g)

reactant moles = 2 , product moles = 2

so pressure has no effect on this equilibrium

problem 2:

2HI (g) <-------------------> H2 (g)+ I2 (g)

reactant moles = 2 , product moles = 2

so pressure has no effect on this equilibrium on doubling the pressure the equilibrium position doesnot shift