Question

How will an increase in pressure affect each of the following systems at equilibrium?

SO₂(g) + NO₂(g) ? NO(g) + SO₃(g)

2H₂O(g) ? 2H₂(g) + O₂(g)

I need help figuring out if the pressure shifts toward the product or toward the reactant or no change for each of those equations.

Thank you for the help!

Answer 1

1) SO₂(g) + NO₂(g) <--------------------> NO(g) + SO₃(g)   . on this equilibrium pressure has no effect

explanation : a)   n= number of moles of products - number of moles of reactants

                                   = (1+1) - (1+1)

                                    = 2-2

                                    =0

there is no change in number of moles . in this case no pressure effect.

2) 2H₂O(g) <------------------------> 2H₂(g) + O₂(g).

on increasing pressure the equilibrium shifts towards backward direction (reactant side)

explanation : a)   n= number of moles of products - number of moles of reactants

                                   = (2+1) - (1+1)

                                    = 3-2

                                    =1

             n > 0

if n > 0 , on increasing pressure the equilibrium shift towards backward direction (reactant side)

finally : pressure effect on equilibrium

1) n =0. equilibrium has no pressure effect

2) n > 0 . equilibrium shifts towards backward (reactant side)

3) n < 0 .equilibrium shifts towards forward (product side)