Paraldehyde is formeed by the polymerisation of:

Options

A. `CH_(3)CHO`
B. `HCHO`
C. `CH_(3)OH`
D. `CH_(3)CH_(2)CHO`.

Explanation

To solve the question "Paraldehyde is formed by the polymerization of:", we will follow these steps:

### Step 1: Identify the compound involved in the polymerization
Paraldehyde is a cyclic trimer of acetaldehyde. Therefore, the first step is to identify the compound that polymerizes to form paraldehyde.

**Hint:** Look for the simplest aldehyde that can undergo polymerization.

### Step 2: Write the structure of acetaldehyde
Acetaldehyde has the chemical formula CH₃CHO. It consists of a methyl group (CH₃) and a formyl group (CHO).

**Hint:** Draw the structure of acetaldehyde to visualize its components.

### Step 3: Understand the polymerization process
In the presence of an acid catalyst (like H⁺), three molecules of acetaldehyde can react together to form paraldehyde through a condensation reaction. This process involves the formation of a cyclic structure.

**Hint:** Remember that polymerization often involves the joining of multiple monomer units.

### Step 4: Draw the structure of paraldehyde
Paraldehyde can be represented as a cyclic compound where three acetaldehyde units are linked together. The structure can be depicted as follows:

```
O
/ \
CH3-CH CH3
\ /
O
/ \
CH3-CH CH3
```

**Hint:** Visualizing the cyclic structure can help understand how the monomers are connected.

### Step 5: Conclude with the answer
From the above steps, we conclude that paraldehyde is formed by the polymerization of acetaldehyde (CH₃CHO).

**Final Answer:** Paraldehyde is formed by the polymerization of acetaldehyde (CH₃CHO).