Name the reaction sequence.
`RCOOH overset(SOCl_2)rarr RCOCl overset(CH_2N_2)rarr RCOCHN_2 overset (H_2O) underset(Ag)rarr RCH_2 COOH`.

Options

A. Arndt-Eistert synthesis
B. Wolff's reaction
C. Reppe's process
D. Wacker's process

Explanation

To solve the problem, we will analyze the given reaction sequence step by step:

1. **Starting Material: Carboxylic Acid (RCOOH)**
- The reaction begins with a carboxylic acid, RCOOH.

2. **First Reaction: Conversion to Acyl Chloride**
- The carboxylic acid reacts with thionyl chloride (SOCl2).
- This reaction converts the carboxylic acid into an acyl chloride (RCOCl) by replacing the hydroxyl group (-OH) with a chlorine atom (-Cl).
- **Reaction:** RCOOH + SOCl2 → RCOCl + SO2 + HCl

3. **Second Reaction: Formation of Diazoketone**
- The acyl chloride (RCOCl) then reacts with diazomethane (CH2N2).
- In this reaction, the chlorine atom is replaced by a diazomethyl group (CH2N2), resulting in the formation of a diazoketone (RCOCHN2).
- **Reaction:** RCOCl + CH2N2 → RCOCHN2 + N2 + HCl

4. **Third Reaction: Hydrolysis in the Presence of Silver**
- The diazoketone (RCOCHN2) undergoes hydrolysis in the presence of water (H2O) and silver (Ag).
- This step leads to the formation of a carboxylic acid with an additional carbon atom (RCH2COOH), effectively extending the carbon chain.
- **Reaction:** RCOCHN2 + H2O + Ag → RCH2COOH + N2 + Ag

5. **Final Product: Homologous Carboxylic Acid**
- The final product of this reaction sequence is RCH2COOH, which is a homolog of the original carboxylic acid (RCOOH).

### Summary of the Reaction Sequence
- The entire reaction sequence can be summarized as:
- RCOOH (carboxylic acid) → RCOCl (acyl chloride) → RCOCHN2 (diazoketone) → RCH2COOH (homologous carboxylic acid)

### Name of the Reaction Sequence
- This reaction sequence is known as **"Arndt-Eistert synthesis."** It is a method for converting a carboxylic acid into its homologous carboxylic acid.