Role of H2O2 as Reducing Agent Steps:

• Recall that a reducing agent donates electrons and gets oxidized; for H2O2, oxidation state of O changes from -1 to 0 (as O2) or -2 (as H2O).
• Examine reaction 1: H2O2 is oxidized (e.g., to O2), so it reduces another species—acts as reducing agent.
• Examine reaction 2: H2O2 is oxidized while reducing a stronger oxidant (e.g., MnO4- to Mn2+), confirming reducing role.
• Examine reaction 3: H2O2 is oxidized (e.g., to H2O), reducing the other reactant—acts as reducing agent. Not enough information on specific reactions to confirm details.

Why C is correct:

• C identifies reactions 2 and 3 where H2O2 undergoes oxidation, per the definition of a reducing agent (loses electrons).

Why the others are wrong:

• A includes reaction 1, where H2O2 likely acts as an oxidizing agent (reduced to H2O).
• B selects only 1, missing the reducing roles in 2 and 3.
• D selects only 2, omitting 3 where H2O2 also reduces.

Final answer: C