Match List I (Oxidation number) with List II (The element) List I List II (Oxidation number) (The element) A. 2 1. Oxidation number of Mn in MnO2 B. 3 2. Oxidation number of S in H2S2O7 C. 4 3. Oxidation number of Ca in CaO2 D. 6 4. Oxidation number of Al in NaAIH4 Codes:

The correct option is A because of the following oxidation state calculations: A matches with 3: In CaO2 calcium peroxide calcium always exhibits an oxidation state of plus 2. The two oxygen atoms together have a charge of minus 2. B matches with 4: In NaAlH4 sodium is plus 1 and hydrogen is minus 1 because it is a metal hydride. To make the molecule neutral aluminum must be plus 3. C matches with 1: In MnO2 each oxygen atom is minus 2 for a total of minus 4. To balance this manganese must be plus 4. D matches with 2: In H2S2O7 hydrogen is plus 1 and oxygen is minus 2. The total charge for two hydrogens is plus 2 and for seven oxygens is minus 14. To reach neutral the two sulfur atoms must provide plus 12 meaning each sulfur is plus 6. Therefore the sequence of List II elements corresponding to the oxidation numbers 2 3 4 and 6 is 3 4 1 2.