To balance the given chemical equation using the oxidation state change method, we need to follow these steps:Step 1: Write the unbalanced equationKMnO4 + KCl + H2SO4 → K2SO4 + MnSO4 + Cl2
Step 2: Identify the elements that undergo oxidation and reductionIn this equation, the oxidation state of Mn changes from +7 to +2, which means it undergoes reduction, while the oxidation state of Cl changes from -1 to 0, which means it undergoes oxidation.
Step 3: Write the half-reactionsReduction half-reaction: MnO4^- → Mn^2+Oxidation half-reaction: Cl^- → Cl2Step 4: Balance the atoms and charges in each half-reactionReduction half-reaction: 8H+ + MnO4^- → Mn^2+ + 4H2OOxidation half-reaction: 2Cl^- → Cl2 + 2e^-Step 5: Balance the electrons in each half-reactionReduction half-reaction: 5e^- + 8H+ + MnO4^- → Mn^2+ + 4H2OOxidation half-reaction: 2Cl^- → Cl2 + 2e^-Step 6: Multiply each half-reaction by a factor to equalize the number of electrons transferredReduction half-reaction: 10e^- + 16H+ + 2MnO4^- → 2Mn^2+ + 8H2OOxidation half-reaction: 14Cl^- → 7Cl2 + 14e^-Step 7: Add the balanced half-reactions together10e^- + 16H+ + 2MnO4^- + 14Cl^- → 2Mn^2+ + 8H2O + 7Cl2Step 8: Cancel out the common terms on both sides of the equation2KMnO4 + 16KCl + 8H2SO4 → 2K2SO4 + 2MnSO4 + 7Cl2 + 8H2OTherefore, the balanced equation using the oxidation state change method is:2KMnO4 + 16KCl + 8H2SO4 → 2K2SO4 + 2MnSO4 + 7Cl2 + 8H2O.