Which (------COOH) group is easaily decarboxylated on heating and why?

Explanation

### Step-by-Step Solution:

1. **Understanding Decarboxylation**: Decarboxylation is the process of removing a carboxyl group (-COOH) from a molecule, resulting in the release of carbon dioxide (CO2). This process is often facilitated by heating.

2. **Identifying Beta-Keto Acids**: Beta-keto acids are a specific class of carboxylic acids that have a ketone group (C=O) adjacent to the carboxylic acid group. The general structure can be represented as R1C(=O)C(=O)OH, where R1 is an alkyl or aryl group.

3. **Mechanism of Decarboxylation in Beta-Keto Acids**: When beta-keto acids are heated, they undergo a rearrangement. The mechanism involves the following steps:
- The hydroxyl group (-OH) of the carboxylic acid can lose a proton (H+), leading to the formation of a carbanion.
...