`underset(aq.)(3HCHO) overset("cooled")hArr X.X` is

Options

A. Formalin
B. Paraformaldehyde
C. Paraldehyde
D. Metaformaldehyde

Answer

To solve the question, we need to analyze the reaction of formaldehyde (HCHO) when it is cooled down. Here’s the step-by-step solution:

### Step 1: Identify the Reactant
The reactant given is formaldehyde, represented as HCHO. In the equation, it is stated as 3HCHO, which indicates that we have three moles of formaldehyde.

### Step 2: Understand the Reaction Condition
The reaction is performed under aqueous conditions (indicated by "aq.") and is then cooled down. Cooling can lead to the formation of a polymer or a cyclic compound from the monomeric formaldehyde.

### Step 3: Determine the Product
When formaldehyde is cooled, it can polymerize to form a cyclic compound known as metaformaldehyde (or trioxane). The structure of metaformaldehyde consists of a cyclic arrangement of three formaldehyde units.

### Step 4: Write the Product
The product formed when 3 moles of HCHO are cooled is metaformaldehyde, which can be represented as:
\[ X = \text{C}_3\text{H}_6\text{O}_3 \]
This indicates that three formaldehyde molecules combine to form a cyclic structure.

### Final Answer
Thus, the product \( X \) when 3HCHO is cooled down is metaformaldehyde.

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