Question

5 Nitryl chloride, NO₂C1, reacts with nitric oxide, NO. The forward reaction is exothermic. NO₂Cl(g) + NO(g) NO₂(g) + NOCI(g) The reaction can reach equilibrium. (a) What is meant by the term equilibrium for a reversible reaction? (b) Explain why increasing the temperature increases the rate of reaction. [2] [3] (c) State and explain the effect, if any, of increasing the temperature on the position of equilibrium. [2] (d) State and explain the effect, if any, of decreasing the pressure on the position of equilibrium. [2]​

Answer 1

(a) Equilibrium for a reversible reaction refers to the state where the rates of the forward and reverse reactions are equal and the concentration of reactants and products remain constant over time. In other words, the reaction reaches a state where the number of molecules of reactants being converted to products is equal to the number of molecules of products being converted back to reactants.

(b) Increasing the temperature increases the rate of reaction because it increases the kinetic energy of the reactant molecules. This means that the molecules are more likely to collide with each other with enough energy to overcome the activation energy barrier and react.

(c) Increasing the temperature shifts the position of equilibrium to the side that absorbs heat. This is because endothermic reactions (reactions that absorb heat) are favored at higher temperatures. In the case of the reaction between nitryl chloride and nitric oxide, the reverse reaction is endothermic and therefore, increasing the temperature would shift the position of equilibrium to the left, favoring the formation of reactants.

(d) Decreasing the pressure shifts the position of equilibrium to the side that has fewer moles of gas. This is because reactions that produce fewer moles of gas are favored at lower pressures. In the case of the reaction between nitryl chloride and nitric oxide, the forward reaction produces fewer moles of gas than the reverse reaction. Therefore, decreasing the pressure would shift the position of equilibrium to the right, favoring the formation of products.