Question

Consider the following reaction. It is occuring in a closed system and it is currently at equilibrium:

2H2O(g) + Heat ↔ 2H2(g) + O2(g)

Label each of the following statements with is effect on the reaction
a) shift towards products b) shift towards reactants c) no change  

Adding water vapor.
Adding hydrogen gas.
Increase the pressure on the reaction vessel
Adding a catalyst to the reaction vessel.
Placing the reaction vessel in an ice bath

Answer 1

1)
Adding reactant will shift the reaction in the direction of product as per Le chatelier Principle
So, Equilibrium moves to product side
Answer: a

2)
Adding product will shift the reaction in the direction of reactant as per Le chatelier Principle
So, Equilibrium moves to reactant side
Answer: b

3)
Increasing pressure will shift the reaction in a direction which have lesser gaseous molecules as per Le chatelier Principle
Here reactant has less gaseous molecule
So equilibrium will move to left
So, Equilibrium moves to reactant side
Answer: b

4)
Catalyst doesn't affect equilibrium
So, No effect on equilibrium
Answer: c

5)
Decreasing Temperature will shift the reaction in a direction which release heat as per Le chatelier Principle
Forward reaction is endothermic in nature
hence, backward reaction will be favoured
So, Equilibrium moves to reactant side
Answer: b