Consider the following reactions:\(\mathrm{H}_{2}(g)+\mathrm{I}_{2}(g) \longrightarrow 2 \mathrm{HI}(g) \quad\) and \(\quad \mathrm{H}_{2}(g)+\mathrm{I}_{2}(s) \longrightarrow 2 \mathrm{HI}(g)\).List two property differences between these two reactions that relate to equilibrium.

The equilibrium constant K is used to express the concentration of the reactants and products at equilibrium. For the given reactions, the equilibrium constants can be written as: For Reaction 1: \(K_1 = \frac{[HI]^2}{[H_2][I_2]^1}\) For Reaction 2: \(K_2 = \frac{[HI]^2}{[H_2][I_2(S)]}\) The phase of Iodine in the second reaction is solid, whereas it is a gas in the first reaction. The concentration of a solid is not included in the equilibrium expression, so the equilibrium constant for the second reaction does not depend on the concentration of solid Iodine. This leads to a difference in the equilibrium constants between the two reactions, as the first reaction's equilibrium constant depends on the concentration of gaseous Iodine, while the second one does not.

A change in pressure affects the equilibrium of a gaseous reaction since the concentrations of the gases are directly proportional to their partial pressures. According to Le Chatelier's principle, an increase in pressure will favor the side of the reaction with fewer moles of gas, while a decrease in pressure will favor the side with more moles of gas. For Reaction 1, both reactants and products are gases. When the pressure is changed, the equilibrium will shift according to Le Chatelier's principle. However, for Reaction 2, one of the reactants is solid. Changes in pressure have negligible effects on the concentration of solids, so the equilibrium of Reaction 2 will not be significantly affected by pressure changes. In conclusion, the two property differences relating to equilibrium for the given reactions are: 1. The equilibrium constant expressions for the two reactions are different due to the difference in Iodine's phase. 2. Pressure change will affect the equilibrium of the first reaction (all gases), but it will not have a significant impact on the equilibrium of the second reaction (involving a solid reactant).