What is the equivalent mass of (Molar mass = M) when it is oxidized to and by nitric acid? — Redox Reactions and Volumetric Analysis Chemistry Question

💡 Solution & Explanation

Arsenic goes from +3 in $As_2S_3$ to +5 in $H_3AsO_4$ (change of 2 per As atom, total = $2 \times 2 = 4$). Sulfur goes from -2 to +6 in $SO_4^{2-}$ (change of 8 per S atom, total = $8 \times 3 = 24$). Total electron transfer (n-factor) = $4 + 24 = 28$. Equivalent mass = M/28.