Calculate the oxidation number of sulphur in `S_2O_8^(2-)` ion.

Explanation

To calculate the oxidation number of sulfur in the \( S_2O_8^{2-} \) ion, we can follow these steps:

### Step 1: Assign oxidation states to oxygen
In most compounds, oxygen has an oxidation state of -2. However, in peroxides, it has an oxidation state of -1. In the case of the \( S_2O_8^{2-} \) ion, we need to consider that there are peroxide linkages present.

### Step 2: Write the oxidation state equation
Let the oxidation state of sulfur be \( x \). In the \( S_2O_8^{2-} \) ion, there are 8 oxygen atoms. If we assume that 6 of these oxygen atoms are in the -2 oxidation state and 2 are in the -1 oxidation state (due to the presence of peroxide), we can set up the following equation based on the total charge of the ion:

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