When arsenic sulphide ( ) is oxidized by concentrated nitric acid ( ), it yields , , and gas. What i — Redox Reactions and Volumetric Analysis Chemistry Question

💡 Solution & Explanation

For $As_2S_3 \to H_3AsO_4 + H_2SO_4$ , As oxidizes from $+3$ to $+5$ (change of 2 for 2 atoms = 4) and S oxidizes from $-2$ to $+6$ (change of 8 for 3 atoms = 24). The total n-factor of $As_2S_3$ is $4 + 24 = 28$ . For $HNO_3 \to NO$ , N reduces from $+5$ to $+2$ . The n-factor of $HNO_3$ is 3. To equalize the electron transfer, cross-multiply their n-factors: 3 moles of $As_2S_3$ strictly require 28 moles of $HNO_3$ . The ratio is $3 : 28$ .