Answer:
Volume of the reaction vessel is increased - shift to the left
The reaction is cooled down - shift to the right
H2 is added to the system - shift to the right
The pressure of the system is decreased - shift to the left
A catalyst is added to the system - no change
Water is removed from the system - shift to the right
Explanation:
When a constraint such as a change in temperature, pressure or volume is imposed on a reaction system in equilibrium, the equilibrium position will shift in such a way as to annul the constraint.
When the volume of a reaction system is increased, the equilibrium position shifts in the direction in which there is the highest total volume. This is the left hand side.
Since the reaction is exothermic (heat is given out) when the reaction is cooled down, the forward reaction is favoured.
Adding of reactants shifts the equilibrium position to the right hand side hence when H2 is added, the equilibrium position shifts to the right.
Decreasing the pressure shifts the equilibrium position to the direction of higher total volume hence the equilibrium shifts to the left when pressure is decreased.
A catalyst has no effect on the equilibrium position. It increases the rate of forward and reverse reaction to the same extent hence the equilibrium position is unaffected.
Removal of water from the system increases the rate of forward reaction since a product is being removed from the reaction system.
