Increasing the pH from 2 to 4 in the redox reaction between Fe2+ and MnO4- in acidic solution will have an effect on the equilibrium position of the reaction. The balanced redox reaction in acidic solution is:5 Fe2+ + MnO4- + 8 H+ 5 Fe3+ + Mn2+ + 4 H2OAs the pH increases from 2 to 4, the concentration of H+ ions decreases. According to Le Chatelier's principle, the equilibrium will shift to counteract this change. In this case, the equilibrium will shift to the left to produce more H+ ions, favoring the formation of Fe2+ and MnO4- ions.This shift in equilibrium will result in a decrease in the concentration of Fe3+ and Mn2+ ions and an increase in the concentration of Fe2+ and MnO4- ions. Consequently, the reaction will be less efficient in oxidizing Fe2+ and reducing MnO4- at a higher pH.