Question

D-(+)- Glyceraldehyde  
The two products formed in above reaction are

• A. Two optically active products
• B. One optically active and one meso product
• C. wo optically inactive products
• D. One optically inactive and one meso product.

Answer 1

The Correct Option is B

When D–(+) Glyceraldehyde undergoes the given reactions, the stereochemistry of the products is determined by the formation of new chiral centers and the possibility of internal symmetry leading to meso compounds.

Reaction with HCN:

The addition of HCN to D–(+) Glyceraldehyde leads to the formation of cyanohydrins. This reaction creates a new chiral center, resulting in the formation of a product that is optically active due to the presence of two stereocenters without internal symmetry.

Reaction with H₂O/H⁺:

This step likely involves hydrolysis or another transformation that maintains or affects the stereochemistry established in the previous step. However, the critical transformation comes in the next step.

Reaction with HNO₃:

Oxidation with HNO₃ can lead to the formation of a diketone or similar structure. If the molecule develops an internal plane of symmetry during this oxidation, it becomes a meso compound. Meso compounds have multiple stereocenters but are optically inactive due to internal symmetry.

Therefore, the overall reaction sequence results in:

One optically active product (from the initial addition of HCN forming a chiral molecule without internal symmetry).

One meso product (from oxidation leading to internal symmetry).

This corresponds to option (3).