Question

The average oxidation state of sulphur in the tetrathionate ion is:

• A. +3
• B. +2.5
• C. +5
• D. +3.5
• E. +1.5

Hint:

To calculate the average oxidation state, assume the oxidation state of known atoms and solve for the unknown.

Answer 1

The Correct Option is B

The tetrathionate ion has the formula \({S}_4{O}_6^{2-}\). We can calculate the average oxidation state of sulfur by assuming that the oxygen is in the -2 oxidation state: \[ 4 \times {Oxidation state of S} + 6 \times (-2) = -2 \] \[ 4 \times {Oxidation state of S} - 12 = -2 \implies 4 \times {Oxidation state of S} = 10 \implies {Oxidation state of S} = +2.5 \]