The reaction between iodine and propanone in the presence of hydrochloric acid catalyst is an example of a reaction with a complex mechanism. The reaction can be represented by the following equation: CH3 2CO + I2 CH3 2CI + HIIn this reaction, hydrochloric acid HCl acts as a catalyst, and the reaction proceeds through the formation of intermediate species. The mechanism of the reaction involves the following steps:1. Formation of the I+ intermediate:HCl + I2 I+ + H+ + Cl-2. Reaction of I+ with propanone to form the intermediate species CH3 2CI+:I+ + CH3 2CO CH3 2CI+3. Formation of the final products: CH3 2CI+ + Cl- CH3 2CI + H+ + I-The rate of the reaction depends on the concentration of the intermediate species, as well as the concentrations of the reactants. The rate law for this reaction can be expressed as:Rate = k[ CH3 2CO][I2]where k is the rate constant, and the concentrations of propanone and iodine are raised to their respective orders in the reaction. In this case, the overall order of the reaction is 2, as the reaction is first-order with respect to both propanone and iodine.The concentration of the intermediate species affects the rate of the reaction because it determines the rate at which the reactants are converted into products. If the concentration of the intermediate species is high, the reaction will proceed faster, as there will be more collisions between the intermediate species and the reactants. Conversely, if the concentration of the intermediate species is low, the reaction will proceed more slowly.In summary, the concentration of intermediate species affects the rate of the reaction between iodine and propanone in the presence of hydrochloric acid catalyst, and the overall order of the reaction is 2.