Exemplar Problems
Problem 1 : Balance the following redox equation occurring in acidic solution:
$$[MnO_4^- + H_2C_2O_4 \rightarrow Mn^{2+} + CO_2]$$
Solution :
To balance this equation, follow these steps:
Step 1: Assign oxidation states to each element: $$[MnO_4^- : Mn^{7+},]$$ $$[H_2C_2O_4 : C^{3+},]$$ $$[Mn^{2+} : Mn^{2+},]$$ $$[CO_2 : C^{4+}.]$$
Step 2: Write down the unbalanced equation: $$[MnO_4^- + H_2C_2O_4 \rightarrow Mn^{2+} + CO_2.]$$
Step 3: Break the reaction into half-reactions for oxidation and reduction: $$[Oxidation: MnO_4^- \rightarrow Mn^{2+},]$$ $$[Reduction: H_2C_2O_4 \rightarrow CO_2.]$$
Step 4: Balance each half-reaction: Oxidation: $$[MnO_4^- \rightarrow Mn^{2+}]$$ Add 5 electrons (eā») to the left side to balance the charge.
Reduction: $$[H_2C_2O_4 \rightarrow CO_2]$$ Add 2 electrons (eā») to the left side to balance the charge.
Step 5: Multiply the half-reactions by coefficients to balance the number of electrons: $$[5(MnO_4^- \rightarrow Mn^{2+})]$$ $$[2(H_2C_2O_4 \rightarrow CO_2)]$$
Step 6: Add the balanced half-reactions to get the overall balanced equation: $$[5MnO_4^- + 16H^+ + 2H_2C_2O_4 \rightarrow 5Mn^{2+} + 8H_2O + 2CO_2.]$$
BETA
