The Newman projection formula of most stable conformation 3-Hydroxypropanal is gauche. It is stable due to :

Options

A. minimum torsional strain
B. intramolecular hydrogen bonding
C. minimum torsional strain and intramolecular hydrogen bonding
D. minimum steric strain

Answer

To determine why the gauche conformation of 3-hydroxypropanal is the most stable, we can follow these steps:

### Step 1: Understand the Structure of 3-Hydroxypropanal
3-Hydroxypropanal has the following structure:
- It consists of a propanal backbone (three carbon atoms with an aldehyde group at one end) and a hydroxyl (OH) group attached to the third carbon.
- The molecular formula can be represented as CH3-CH(OH)-CH2-CHO.

### Step 2: Draw the Newman Projection
To analyze the conformations, we draw the Newman projection:
- Identify the front and back carbon atoms. In this case, we will consider the carbon atoms of the aldehyde group and the carbon with the hydroxyl group.
- The front carbon (C1) has the aldehyde group (CHO) and the back carbon (C2) has the hydroxyl group (OH).

### Step 3: Identify the Conformations
- The most stable conformation is the gauche conformation, which occurs when the bulky groups (OH and CHO) are staggered but close enough to allow for intramolecular hydrogen bonding.
- The other conformations include fully eclipsed and fully staggered forms, which are less stable due to increased torsional strain.

### Step 4: Analyze Stability Factors
- The stability of the gauche conformation can be attributed to the presence of intramolecular hydrogen bonding between the hydroxyl group (OH) and the carbonyl oxygen (C=O).
- This hydrogen bonding stabilizes the molecule by lowering the energy of the system.

### Step 5: Conclusion
The most stable conformation of 3-hydroxypropanal is the gauche conformation due to the presence of intramolecular hydrogen bonding, which provides additional stability compared to other conformations.

### Final Answer
The gauche conformation of 3-hydroxypropanal is stable due to intramolecular hydrogen bonding.

---