$\mathrm{D}-(+)-$Glyceraldehyde $\underset{\begin{array}{l}\mathrm{ii})\hspace{0.17em}{\mathrm{H}}_{\mathrm{2}}\mathrm{O}/{\mathrm{H}}^{\mathrm{+}}\\ \mathrm{iii})\hspace{0.17em}{\mathrm{HNO}}_{\mathrm{3}}\end{array}}{\overset{\mathrm{i})\hspace{0.17em}\mathrm{HCN}}{\to }}$

The products formed in the above reaction are

The sequence: D-(+)-Glyceraldehyde → i) HCN ii) H₂O/H⁺ iii) HNO₃

gives two different tartaric acids: one meso and one optically active.

Stepwise Explanation

1. HCN Addition (Kiliani–Fischer cyanohydrin synthesis):
   • D-(+)-Glyceraldehyde reacts with HCN to form two stereoisomeric cyanohydrins (introduction of a new chiral center).
2. Hydrolysis (H₂O/H⁺):
   • The cyanohydrins are hydrolyzed to yield two different four-carbon aldonic acids (aldotetronic acids).
3. Oxidation (HNO₃):
   • The aldonic acids are further oxidized by HNO₃ to give two stereoisomeric tartaric acids:
     • One is meso-tartaric acid (achiral, optically inactive due to internal symmetry).
     • The other is D-(+)-tartaric acid (chiral, optically active).

Final Products

• Meso-tartaric acid (optically inactive)
• D-(+)-tartaric acid (optically active)

These are exactly the structures shown in your image: one with mirror symmetry (meso) and one that is optically active. Thus, these are the two products formed from the Kiliani–Fischer synthesis starting from D-(+)-glyceraldehyde through the given steps.