The iodine clock reaction is a classical chemical reaction that involves the reaction between potassium iodate KIO and sodium bisulfite NaHSO in the presence of an acid. The reaction can be represented by the following equations:1 KIO + 3 NaHSO KI + 3 NaHSO2 KI + HO + I 2 KIOIn the iodine clock reaction, iodine I is produced in the first reaction and then consumed in the second reaction. The rate of the reaction can be determined by monitoring the appearance of iodine, which can be detected by its color change when it reacts with a starch indicator.The pH of the reaction mixture plays a crucial role in the rate of the iodine clock reaction. The reaction between potassium iodate and sodium bisulfite is acid-catalyzed, which means that the reaction rate increases as the acidity of the reaction mixture increases lower pH . This is because the presence of H ions protons from the acid helps to facilitate the reaction between the reactants.When the pH of the reaction mixture is increased more basic , the concentration of H ions decreases, which in turn slows down the reaction rate. Conversely, when the pH of the reaction mixture is decreased more acidic , the concentration of H ions increases, leading to a faster reaction rate.In summary, changing the pH of the reaction mixture affects the rate of the iodine clock reaction between potassium iodate and sodium bisulfite. Lowering the pH increasing acidity will increase the reaction rate, while increasing the pH decreasing acidity will decrease the reaction rate.