When adipic acid is heated, the product is .

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Answer

To determine the product formed when adipic acid is heated, we can follow these steps:

### Step 1: Identify the Structure of Adipic Acid
Adipic acid is a six-carbon dicarboxylic acid with the following structure:
- It has two carboxylic acid groups (-COOH) at each end of the carbon chain.
- The structural formula can be represented as:

\[ HOOC-CH_2-CH_2-CH_2-CH_2-COOH \]

### Step 2: Understand the Heating Process
When adipic acid is heated, it undergoes a dehydration reaction. This means that certain groups will be removed from the molecule, leading to the formation of a cyclic compound.

### Step 3: Identify the Byproducts
During the heating of adipic acid:
- Carbon dioxide (CO₂) is released.
- Water (H₂O) is also eliminated.

### Step 4: Formation of the Product
As a result of the loss of CO₂ and H₂O, the remaining structure will form a five-membered ring. The process can be visualized as follows:
- The two carboxylic acid groups react with each other, leading to the formation of a cyclic compound.
- The structure of the resulting compound will have a five-membered ring with one oxygen atom and four carbon atoms, resulting in a compound known as a lactone.

### Step 5: Final Structure
The final structure after the heating process can be represented as:

\[ \text{Cyclic structure with 5 carbons and 1 oxygen} \]

This compound is known as a cyclic anhydride or lactone.

### Conclusion
The product formed when adipic acid is heated is a five-membered cyclic compound, specifically a lactone.

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