The answer to each of the following is a non-negative integer.
The sum of oxidation state of all sulphur atoms in pentathionate ion is………..

Answer

To find the sum of the oxidation states of all sulfur atoms in the pentathionate ion, we can follow these steps:

### Step 1: Understand the structure of the pentathionate ion
The pentathionate ion (S5O6^2-) consists of five sulfur atoms and six oxygen atoms. The structure can be represented as follows:

- S(=O)2 - S - S - S - S(=O)2

### Step 2: Assign oxidation states
To find the oxidation states of the sulfur atoms, we need to analyze the bonding and the overall charge of the ion.

1. **Identify the oxidation states of the oxygen atoms**:
- Each oxygen atom typically has an oxidation state of -2. However, in the case of double-bonded oxygen (like in S=O), it still remains -2.

2. **Calculate the total oxidation state contribution from oxygen**:
- There are 6 oxygen atoms, contributing a total of 6 * (-2) = -12.

### Step 3: Set up the equation for the total oxidation state
Let the oxidation states of the five sulfur atoms be S1, S2, S3, S4, and S5. The total oxidation state of the pentathionate ion can be expressed as:

\[ S1 + S2 + S3 + S4 + S5 + (-12) = -2 \]

This is because the overall charge of the pentathionate ion is -2.

### Step 4: Rearranging the equation
Rearranging the equation gives us:

\[ S1 + S2 + S3 + S4 + S5 = -2 + 12 \]
\[ S1 + S2 + S3 + S4 + S5 = 10 \]

### Step 5: Conclusion
Thus, the sum of the oxidation states of all sulfur atoms in the pentathionate ion is **10**.

### Final Answer
The sum of oxidation states of all sulfur atoms in pentathionate ion is **10**.

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