This equation shows an equilibrium established in the synthesis of ammonia from its component gases: N₂(g) + 3H₂(g) ⇌ 2NH₃(g) If the volume of the reaction chamber is suddenly halved at time T, which of the following best depicts changes in the concentration of ammonia over time? - HSC - SSCE Chemistry - Question 14 - 2060 - Paper 1

When the volume of the reaction chamber is halved, the pressure increases due to the gas law, causing the equilibrium position to shift towards the side with fewer moles of gas in accordance with Le Chatelier's principle. Given that the forward reaction produces 2 moles of NH₃(g) from 4 moles of reactants (1 mole of N₂ and 3 moles of H₂), this means that the concentration of NH₃ would increase over time as the reaction shifts to re-establish equilibrium. Thus, the graph depicting this change would show an initial increase in the concentration of ammonia.