The effect of temperature on the equilibrium constant K of a reaction can be determined using the van't Hoff equation. The reaction between iodine and propanone is an exothermic reaction, which means it releases heat. The balanced equation for this reaction is:CH3COCH3 aq + I2 aq CH3COCH2I aq + HI aq In an exothermic reaction, increasing the temperature will shift the equilibrium position towards the reactants, favoring the reverse reaction. Consequently, the equilibrium constant K will decrease with an increase in temperature. Conversely, if the temperature is decreased, the equilibrium will shift towards the products, and the equilibrium constant K will increase.In summary, for the reaction between iodine and propanone, the equilibrium constant K decreases with an increase in temperature and increases with a decrease in temperature.