The iodine clock reaction between potassium persulfate K2S2O8 and potassium iodide KI is a well-known chemical reaction used to study reaction kinetics. The effect of changing temperature and pressure on the equilibrium constant and reaction rate can be analyzed separately.1. Effect of temperature:According to the Arrhenius equation, the reaction rate constant k is related to temperature T as follows:k = Ae^-Ea/RT where A is the pre-exponential factor, Ea is the activation energy, R is the gas constant, and T is the temperature in Kelvin.As the temperature increases, the reaction rate constant k increases, which means the reaction rate will also increase. This is because, at higher temperatures, the molecules have more kinetic energy, leading to more frequent and energetic collisions between reactants, increasing the probability of successful reactions.The equilibrium constant K is also affected by temperature changes. According to the van 't Hoff equation:ln K2/K1 = -H/R 1/T2 - 1/T1 where K1 and K2 are the equilibrium constants at temperatures T1 and T2, respectively, and H is the standard enthalpy change of the reaction.If the reaction is endothermic H > 0 , increasing the temperature will increase the equilibrium constant K , shifting the equilibrium towards the products. If the reaction is exothermic H < 0 , increasing the temperature will decrease the equilibrium constant K , shifting the equilibrium towards the reactants.2. Effect of pressure:The iodine clock reaction between potassium persulfate and potassium iodide occurs in a solution, and the pressure has a minimal effect on the reaction rate and equilibrium constant. This is because the reaction involves dissolved ions in an aqueous solution, and changes in pressure do not significantly affect the concentrations or the behavior of the ions.In summary, increasing the temperature will increase the reaction rate and can either increase or decrease the equilibrium constant, depending on the enthalpy change of the reaction. Pressure changes have minimal effects on the iodine clock reaction between potassium persulfate and potassium iodide.