`CH_(2)OHCH_(2)OH` on heating with periodic acid gives

Options

A.
B. `2CO_(2)`
C. `2HCOOH`
D. `{:(CHO),(|),(CHO):}`

Explanation

To solve the problem of what product is formed when ethylene glycol (CH₂OH-CH₂OH) is heated with periodic acid (HIO₄), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The compound given is ethylene glycol, which has the formula CH₂OH-CH₂OH.
- The reagent used is periodic acid, represented as HIO₄.

2. **Understand the Reaction**:
- Periodic acid is known to oxidize glycols. In this case, it will cleave the carbon-carbon bond in ethylene glycol and oxidize the hydroxyl groups.

3. **Reaction Mechanism**:
- When ethylene glycol reacts with periodic acid, it undergoes oxidative cleavage. The two hydroxyl (-OH) groups are oxidized, and the carbon-carbon bond between the two carbon atoms is broken.
- This results in the formation of two molecules of formaldehyde (HCHO).

4. **Write the Balanced Equation**:
- The reaction can be summarized as:
\[ \text{CH}_2\text{OH-CH}_2\text{OH} + \text{HIO}_4 \rightarrow 2 \text{HCHO} + \text{HIO}_3 + \text{H}_2\text{O} \]
- Here, two moles of formaldehyde (HCHO) are produced, along with iodic acid (HIO₃) and water (H₂O).

5. **Identify the Products**:
- From the balanced equation, we see that the primary product formed is formaldehyde (HCHO).
- Therefore, the answer to the question is that ethylene glycol on heating with periodic acid gives formaldehyde.

### Final Answer:
The product formed when CH₂OH-CH₂OH is heated with periodic acid is **formaldehyde (HCHO)**.

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