Balance the following equation: KMnO 4 + H 2 C 2 O 4 + H 2 SO 4 → MnSO 4 + K 2 SO 4 + H 2 O + CO 2

This is a redox reaction, which can be balanced by the oxidation number method as explained below: The skeleton equation along with the oxidation number of each atom is written below: KMnO 4 + 1 + 7 - 2 + H 2 SO 4 + 1 + 6 - 2 + H 2 C 2 O 4 + 1 + 3 - 2 → K 2 SO 4 + 1 + 6 - 2 + MnSO 4 + 2 + 6 - 2 + CO 2 + 4 - 2 + H 2 O + 1 - 2 In the above reaction, carbon undergoes oxidation as its oxidation number increases from + 3 in H 2 C 2 O 4 to + 4 in CO 2 (Oxidation number increases by one unit per atom or two for two atoms). Mn undergoes reduction as its oxidation number decreases from + 7 in KMnO 4 to + 2 in MnSO 4 (Oxidation number decreases by five units per atom). In order to balance the increase and decrease of oxidation numbers, multiply H 2 C 2 O 4 by 5 and KMnO 4 by 2 , then we get, 2 KMnO 4 + H 2 SO 4 + 5 H 2 C 2 O 4 → K 2 SO 4 + MnSO 4 + CO 2 + H 2 O To balance the number of Mn and C atoms whose oxidation number changes during the reaction, multiply MnSO 4 by 2 and CO 2 by 10 , then we get, 2 KMnO 4 + H 2 SO 4 + 5 H 2 C 2 O 4 → K 2 SO 4 + 2 MnSO 4 + 10 CO 2 + H 2 O To balance sulphur atoms whose oxidation number does not change during the reaction, add 3 H 2 SO 4 molecules, then we get, 2 KMnO 4 + 3 H 2 SO 4 + 5 H 2 C 2 O 4 → K 2 SO 4 + 2 MnSO 4 + 10 CO 2 + H 2 O To balance hydrogen and oxygen atoms multiply H 2 O by 8 , then we get, 2 KMnO 4 + 3 H 2 SO 4 + 5 H 2 C 2 O 4 → K 2 SO 4 + 2 MnSO 4 + 10 CO 2 + 8 H 2 O Hence, the balanced equation becomes as given below: 2 KMnO 4 + 3 H 2 SO 4 + 5 H 2 C 2 O 4 → K 2 SO 4 + 2 MnSO 4 + 10 CO 2 + 8 H 2 O .