The oxidation number of four sulphur atoms in tetrathionate ion are

Options

A. 2.5,2.5,2.5,2.5
B. 5,0,0,5
C. 3,2,2,3
D. 4,1,1,4

Answer

To determine the oxidation number of the four sulfur atoms in the tetrathionate ion (S4O6^2-), we can follow these steps:

### Step 1: Write the formula of the tetrathionate ion
The formula of the tetrathionate ion is S4O6^2-. This indicates that there are four sulfur (S) atoms and six oxygen (O) atoms in the ion.

**Hint:** Start by identifying the molecular formula of the ion to understand the composition.

### Step 2: Assign oxidation states to oxygen
In most compounds, oxygen has an oxidation state of -2. Since there are six oxygen atoms in the tetrathionate ion, the total contribution from oxygen to the charge is:
\[ 6 \times (-2) = -12 \]

**Hint:** Remember that oxygen typically has an oxidation state of -2 unless it is in a peroxide or superoxide.

### Step 3: Set up the equation for the overall charge
The tetrathionate ion has an overall charge of -2. Therefore, we can set up the following equation to find the total oxidation state of the sulfur atoms (let's denote the oxidation state of sulfur as x):
\[ 4x + (-12) = -2 \]

**Hint:** Use the known overall charge of the ion to set up an equation involving the oxidation states.

### Step 4: Solve for the oxidation state of sulfur
Now, we can solve the equation:
\[ 4x - 12 = -2 \]
Adding 12 to both sides gives:
\[ 4x = 10 \]
Dividing both sides by 4 gives:
\[ x = 2.5 \]

**Hint:** Isolate the variable to find the oxidation state.

### Step 5: Determine the individual oxidation states of sulfur atoms
In the tetrathionate ion, there are different types of sulfur atoms. The terminal sulfur atoms (the ones at the ends) typically have a higher oxidation state, while the central sulfur atoms have a lower oxidation state.

- The terminal sulfur atoms have an oxidation state of +5.
- The central sulfur atoms have an oxidation state of 0.

Thus, the oxidation states of the four sulfur atoms can be summarized as:
- 2 sulfur atoms at +5
- 2 sulfur atoms at 0

**Hint:** Recognize that different sulfur atoms can have different oxidation states based on their position in the ion.

### Final Answer
The oxidation numbers of the four sulfur atoms in the tetrathionate ion (S4O6^2-) are +5, +5, 0, and 0.