Which of the following reaction(s) is relevant to the microcosmic salt bead test? — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

Step 1: This represents a redox reaction where manganese dioxide (MnO2) acts as an oxidizing agent in an acidic medium. Step 2: Oxalate (C2O42-) is oxidized by MnO2 and dilute H2SO4 to carbon dioxide gas (CO2), while MnO2 is reduced to Mn2+: C2O42- + MnO2 + 4H+ -> Mn2+ + 2CO2↑ + 2H2O. Step 3: Therefore, the evolved gas is CO2, which corresponds to option (a).