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Question: Iodine oxidises \({S_2}{O_3}^{ - 2}\) ion into : \(S{O_3}^{ - 2}\) \(S{O_4}^{ - 2}\) \({S_4}...

Iodine oxidises S2O3−2{S_2}{O_3}^{ - 2} ion into :
SO3−2S{O_3}^{ - 2}
SO4−2S{O_4}^{ - 2}
S4O6−2{S_4}{O_6}^{ - 2}
S−2{S^{ - 2}}

Explanation

Solution

Iodine belongs to group 17 , the halogen family . All the halogens have a strong tendency to accept an electron and therefore act as a strong oxidising agent . Their oxidising power decreases from F2{F_2} to I2{I_2} .

Complete step by step answer:
An oxidizing agent is referred to as a chemical compound that readily transfers oxygen atoms or a substance that gains electrons in a redox chemical reaction . It is a substance which oxidises the other compound and itself gets reduced .
Iodine is the weakest oxidising agent in the halogen family as oxidising power of halogens decreases from F2{F_2} to I2{I_2} .
When iodine oxidises S2O3−2{S_2}{O_3}^{ - 2} the following reaction takes place .
I2+2S2O3−2→S4O6−2+2I−{I_2} + 2{S_2}{O_3}^{ - 2} \to {S_4}{O_6}^{ - 2} + 2{I^ - }
As you can see in the above reaction iodine oxidises S2O3−2{S_2}{O_3}^{ - 2} to S4O6−2{S_4}{O_6}^{ - 2} and itself gets reduced to iodide ion .
The valency of sulphur changes from +2 to +2.5 ( this is the average oxidation state since in this ion all the sulphurs have different oxidation states ) , whereas the oxidation of iodine changes from 0 to +1 .

So, the correct answer is Option C .

Note:
In S4O6−2{S_4}{O_6}^{ - 2} the valency of two sulphur atoms which form a bridge that is they are attached to each other have a valency of -1 whereas the other two sulphur atoms have a valency of +6 as they are attached to three oxygen atoms each . Therefore the average valency of all the four sulphur atoms is +4 .