Primary alcohols can be obtained from the reaction of the RMgX with :

Options

A. `CO_(2)`
B. HCHO
C. `CH_(3)CHO`
D. `H_(2)O`

Answer

To obtain primary alcohols from the reaction of RMgX (Grignard reagent), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Grignard Reagent (RMgX)**:
- RMgX is a Grignard reagent where R is an alkyl or aryl group and X is a halogen (like Cl, Br, or I). The R group is nucleophilic in nature, meaning it has a negative charge.

2. **Identifying Primary Alcohol**:
- A primary alcohol is defined as an alcohol where the hydroxyl (-OH) group is attached to a carbon that is connected to only one other carbon atom. For example, CH3CH2OH (ethanol) is a primary alcohol.

3. **Reaction with Formaldehyde**:
- When RMgX reacts with formaldehyde (HCHO), the nucleophilic R group attacks the carbon of the carbonyl group in formaldehyde. The reaction can be represented as:
\[ R-MgX + HCHO \rightarrow R-CH2OH + MgXOH \]
- In this reaction, the R group adds to the carbon of formaldehyde, leading to the formation of a primary alcohol (R-CH2OH).

4. **Hydrolysis**:
- After the addition of the Grignard reagent to formaldehyde, hydrolysis is performed. This involves adding water (H2O) to the reaction mixture, which converts the magnesium alkoxide intermediate into a primary alcohol and a magnesium hydroxide salt:
\[ R-CH2-MgX + H2O \rightarrow R-CH2OH + Mg(OH)X \]

5. **Conclusion**:
- Therefore, the primary alcohol can be obtained from the reaction of RMgX with formaldehyde (HCHO).

### Final Answer:
Primary alcohols can be obtained from the reaction of RMgX with **formaldehyde (HCHO)**.

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