Predict what will happen to the ammonia equilibrium system if hydrogen gas (h2) is added in the following reaction. n2(g) + 3h2(g) two arrows stacked on top of each other. the top arrow points to the right. the bottom arrow points to the left. 2nh3(g the equilibrium shifts to the left. the reaction reaches completion. the equilibrium remains the same. the equilibrium shifts to the right.

Correct answer is option C i.e. The equilibrium shifts to the right.

Reason:
Following reaction is involved in present case:
N2 (g)     +         3H2 (g)       ⇄     2NH3(g)     

Now, according to Le Chatelier's  principle, if pressure is increased/decreased in system, the reaction equilibrium will move in direction to minimize this effect.  So, if H2 is added in reaction system, it will increase pressure of reaction system. Hence, equilibrium will shift towards right, so as to minimize the effect of increasing pressure.  

Ithink answer is cast?