Calculate the oxidation number of the underlined element in the following molecules.
`Na_(2)ul(S_(4))O_(6)`

Explanation

To calculate the oxidation number of sulfur in the molecule \( \text{Na}_2\text{S}_4\text{O}_6 \), we will follow these steps:

### Step 1: Identify the oxidation states of known elements
- Sodium (\( \text{Na} \)) is an alkali metal and has an oxidation state of \( +1 \).
- Oxygen (\( \text{O} \)) typically has an oxidation state of \( -2 \).

### Step 2: Set up the equation for the oxidation states
In the molecule \( \text{Na}_2\text{S}_4\text{O}_6 \):
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