Which of the following statements rigorously describe the variation in equivalent weights of primary — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question
Question
Which of the following statements rigorously describe the variation in equivalent weights of primary oxidizing and reducing agents across different chemical media? (Assume $M$ represents the respective molar mass).
💡 Solution & Explanation
Step 1: Evaluate $KMnO_4$. In acidic medium, $Mn^{+7} \rightarrow Mn^{+2}$ (change of 5 $\Rightarrow$ E = M/5). In neutral/weakly alkaline medium, $Mn^{+7} \rightarrow Mn^{+4}$ (change of 3 $\Rightarrow$ E = M/3). In strongly alkaline medium, $Mn^{+7} \rightarrow Mn^{+6}$ (change of 1 $\Rightarrow$ E = M/1). Options A, C, and D are correct. Step 2: Evaluate $K_2Cr_2O_7$. In acidic medium, $Cr_2O_7^{2-} \rightarrow 2Cr^{3+}$. The oxidation state of each Cr changes from +6 to +3. Since there are 2 Cr atoms, total change = $2 \times 3 = 6$ (n-factor = 6 $\Rightarrow$ E = M/6). Option B is correct.