Many factors can influence the shift in the equilibrium of reactions, these factors are: amount of reactants or products, temperature, pressure, and a few more. Any change in each factor will cause a shift in the reaction towards one of the sides, and when we are talking about pressure, a simple rule might be followed:
When there is an increase of pressure, the equilibrium will shift towards the side of the reaction with fewer moles of gas, since pressure and volume are connected, if I have too much of something and only a few on the other side, the expected is that pressure will tend to go towards the side with less amount of the compound
When there is a decrease in pressure, the opposite will occur, the equilibrium will shift towards the side with more moles of gas
In our question we have
N2 + 3 H2 -> 2 NH3 + heat
Reactants side: 4 moles
Produtcs side: 3 moles (heat might count)
Therefore with an increase of pressure, the equilibrium will shift towards the products side, to the right, because there are fewer moles of gas
Letter B
