What stress will shift the following equilibrium system to the left? N2 (g) + 3H2 (g) ⇌ 2NH3 (g)

Answer;

Decrease in pressure

Explanation; If the pressure of a system is increased, the reaction will shift toward the side with fewer moles of gas, whereas when the pressure of a system is decreased, the reaction will shift toward the side with more moles of gas. In this case; If the pressure of the system with the above reaction decreases, the reaction will shift to the left. The reactants side has more moles of gas, so the reaction will shift toward the direction of the reactants.