The anhydride of pyrosulphuric acid is

Options

A. `SO_(2)`
B. `S_(2)O_(3)^(2-)`
C. `SO_3`
D. `S_(2)O_(7)^(2-)`

Answer

To determine the anhydride of pyrosulfuric acid, we will follow these steps:

### Step 1: Understand the Structure of Pyrosulfuric Acid
Pyrosulfuric acid, also known as oleum, has the following structure:
- It consists of two sulfur atoms and multiple oxygen atoms, including hydroxyl (OH) groups.

### Step 2: Write the Chemical Formula
The chemical formula for pyrosulfuric acid can be represented as H2S2O7. This indicates that it contains two sulfur atoms, seven oxygen atoms, and two hydrogen atoms.

### Step 3: Define Anhydride
An anhydride is formed when water (H2O) is removed from an acid. In this case, we will remove water from pyrosulfuric acid.

### Step 4: Eliminate Water from the Structure
To find the anhydride, we need to remove one molecule of water (H2O) from the pyrosulfuric acid:
- When we remove H2O from H2S2O7, we are left with S2O6.

### Step 5: Identify the Anhydride
The anhydride of pyrosulfuric acid is actually sulfur trioxide (SO3). When two molecules of SO3 combine, they can form the structure of pyrosulfuric acid (H2S2O7).

### Conclusion
Thus, the anhydride of pyrosulfuric acid is 2SO3.

### Final Answer
The anhydride of pyrosulfuric acid is **2SO3**.

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