What is the average oxidation state of Sulphur in the tetrathionate ion ()? — Redox Reactions and Volumetric Analysis Chemistry Question

💡 Solution & Explanation

Mathematically, let x be the average O.S. of Sulphur. $4x + 6(-2) = -2 \Rightarrow 4x = 10 \Rightarrow x = +2.5$. Structurally, the terminal sulfur atoms are +5, and the central S-S bonded atoms are 0. The average is $(5+0+0+5)/4 = 2.5$.