Complete the following reactions by identitying A:
`A+ "Hydrogen" (g) overset(Pd//BaSO_(4))to (CH_3)_2CH-CHO`

Explanation

To identify compound A in the given reaction, we need to analyze the transformation that occurs when A reacts with hydrogen gas (H₂) in the presence of a palladium catalyst on barium sulfate (Pd/BaSO₄) to yield the product (CH₃)₂CH-CHO, which is an aldehyde.

### Step-by-Step Solution:

1. **Identify the Product**: The product given is (CH₃)₂CH-CHO. This structure indicates that we have a branched aldehyde with two methyl groups attached to the second carbon of a three-carbon chain, making it 2-methylpropanal.

2. **Understand the Reaction Conditions**: The reaction conditions involve hydrogen gas and a palladium catalyst on barium sulfate. This setup is typically used for the selective reduction of acid chlorides to aldehydes.

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