Chemistry - STEREO ISOMERISM Question with Solution | TestHub

Question Explanation: Identify the compound that can form two products when treating with ${\mathrm{NH}}_2\mathrm{OH}$ (hydroxylamine).

Concept:

Aldehyde/Ketone reaction with Hydroxylamine (Oxime formation and GI).

Solution:

Reaction with ${\mathrm{NH}}_2\mathrm{OH}$ forms an oxime $(\mathrm{C}=\mathrm{NOH})$. Two products (syn/anti or $\mathrm{E}/\mathrm{Z}$ geometrical isomers) are formed if the $\mathrm{C}=\mathrm{N}$ bond exhibits GI .

GI requires the C atom to be asymmetrically substituted $\left(\mathrm{R}\ne {\mathrm{R}}^{\prime }\right)$.

A. Acetaldehyde $\left({\mathrm{CH}}_3\mathrm{CHO}\right)$ : C is attached to ${\mathrm{CH}}_3$ and $\mathrm{H}\left(\mathrm{R}\ne {\mathrm{R}}^{\prime }\right)$. ✓

B. Acetone $\left({\mathrm{CH}}_3{\mathrm{COCH}}_3\right):\mathrm{C}$ is attached to ${\mathrm{CH}}_3$ and ${\mathrm{CH}}_3\left(\mathrm{R}={\mathrm{R}}^{\prime }\right).\times$

C. Formaldehyde $(\mathrm{HCHO})$ : C is attached to H and $\mathrm{H}\left(\mathrm{R}={\mathrm{R}}^{\prime }\right).\times$

D. Benzophenone $\left({\mathrm{Ph}}_2\mathrm{C}=\mathrm{O}\right)$ : C is attached to Ph and $\mathrm{Ph}\left(\mathrm{R}={\mathrm{R}}^{\prime }\right).\times$

Final Answer: Option (A)