**Match Column I with Column II (Reactions in acidic medium):** <br> **Column I:** <br> (A) <br> (B) — Redox Reactions and Volumetric Analysis Chemistry Question
Question
**Match Column I with Column II (Reactions in acidic medium):** <br> **Column I:** <br> (A) $MnO_4^- \rightarrow Mn^{2+}$ <br> (B) $Cr_2O_7^{2-} \rightarrow 2Cr^{3+}$ <br> (C) $FeC_2O_4 \rightarrow Fe^{3+} + 2CO_2$ <br> (D) $As_2S_3 \rightarrow 2AsO_4^{3-} + 3SO_4^{2-}$ <br> **Column II:** <br> (p) $n = 3$ <br> (q) $n = 5$ <br> (r) $n = 6$ <br> (s) $n = 28$
💡 Solution & Explanation
**Logic:** <br> (A) $Mn^{+7} \rightarrow Mn^{+2}$ involves gain of $5e^-$, so $n=5$. <br> (B) $2Cr^{+6} \rightarrow 2Cr^{+3}$ involves gain of $2 \times 3 = 6e^-$, so $n=6$. <br> (C) $Fe^{2+} \rightarrow Fe^{3+}$ ($1e^-$) and $C_2O_4^{2-} \rightarrow 2CO_2$ ($2e^-$). Total $n = 1+2=3$. <br> (D) $2As^{3+} \rightarrow 2As^{5+}$ ($4e^-$) and $3S^{2-} \rightarrow 3S^{6+}$ ($24e^-$). Total $n = 4+24=28$.