Which of the following changes will increase the amount of NO(g) in the reaction $2{\mathrm{N}}_2\mathrm{O}\left(g\right)+{\mathrm{O}}_2\left(g\right)⟶4\mathrm{NO}\left(g\right)?$

Solution:

Removal of ${\mathrm{O}}_2\left(\mathrm{g}\right)$ causes the reaction to shift in the backward direction and thus decreases the amount of NO(g). Decreasing volume implies increase in pressure. The reaction will be affected to decrease the pressure (i.e. decrease in gaseous species). This will also decrease the amount of NO(g) Addition of catalyst has no effect on equilibrium position. Addition ofN₂O (g) shift the reaction in the forward direction and hence increase the amount of NO(g).