In the reaction sequence
`RCOCl+H_(2)overset(Pd+BaSO_(4))rarrAoverset(HCN)rarrBoverset(H_(3)O^(o+))rarrC`
A,B and C are given by the set :-

Options

A. `RCHO,RCH(OH)CN, RCH(OH)CH_(2)NH_(2)`
B. `RCHO, RCH(OH)CN, RCH(OH)COOH`
C. `RCHO,R-underset(O)underset(||)C-underset(CN)underset(|)CH_(2),R-underset(O)underset(||)C-OH`
D. `RCHO,R-CH_(2)-CN,R-CH_(2)-COOH`

Answer

To solve the given reaction sequence, we will analyze each step carefully.

### Step-by-Step Solution:

1. **Identify the Starting Material**:
The starting material is RCOCl (an acyl chloride).

2. **First Reaction**:
The first reaction involves RCOCl reacting with H2 in the presence of Pd/BaSO4. This is a Rosenmund reduction, which converts acyl chlorides to aldehydes.
- **Product A**: The product of this reaction is RCHO (an aldehyde).

3. **Second Reaction**:
The aldehyde (RCHO) then reacts with HCN (hydrogen cyanide). In this reaction, the carbonyl carbon of the aldehyde is attacked by the cyanide ion (CN⁻), leading to the formation of a cyanohydrin.
- **Product B**: The product of this reaction is RCH(OH)CN (the cyanohydrin).

4. **Third Reaction**:
The cyanohydrin (RCH(OH)CN) is then treated with H3O⁺ (acidic conditions). Under acidic conditions, the cyanohydrin undergoes hydrolysis, converting the cyano group (CN) into a carboxylic acid (COOH).
- **Product C**: The final product is RCOOH (a carboxylic acid).

### Summary of Products:
- **A**: RCHO (aldehyde)
- **B**: RCH(OH)CN (cyanohydrin)
- **C**: RCOOH (carboxylic acid)

### Final Answer:
The correct set of products A, B, and C is:
- A = RCHO
- B = RCH(OH)CN
- C = RCOOH