Question

What happens to the equilibrium when the pressure increased

Answer 1

When a reversible reaction is occurring and the pressure is increased then the equilibrium which is dynamic will shift in order to facilitate this change by virtue of Le Chatelier's principle.  When pressure is increased, the equilibrium shifts to favor the side with the most number of moles.

For example, the theoretical formation of ammonia is characterized by the reaction:   N₂   +   3H₂    ⇆   2NH₃ 
If the pressure is increased in this reaction system, then the equilibrium would shift to the left, since that side has three moles of hydrogen and one mole of nitrogen for a total of four moles while the right side only has two moles.

Answer 2

Answer:

Position of equilibrium changes with increase in pressure but equilibrium constant remains same

Explanation:

For a reaction - $A(g)\rightleftharpoons 2B(g)$, equilibrium shifts toward left with increase in pressure.

Because, number of gas molecules increases in forward direction which means pressure increases in forward direction. According to Le-chatlier principle, equilibrium will shift toward backward direction or towards left to minimize the increased pressure as well as keep the equilibrium constant same.

For a reaction- $2B(g)\rightleftharpoons A(g)$, equilibrium shifts toward right with increase in pressure.

Explanation for this is same as above.