Question

Which is the reagent used for the following conversion?

• A. NaCN/HCl
• B. NaBH$_4$
• C. SOCl$_2$
• D. O$_3$/Zn-H$_2$O
• E. [Ag(NH$_3$)$_2$]$^+$

Hint:

Chemistry Tip: If a reaction diagram is missing in OCR text, always rely on the official key and original structure because reagent questions are structure-sensitive.

Answer 1

Answer: (E)

Concept:
This question depends on the specific reaction scheme shown in the paper image. From the official answer key, the correct reagent is option (E). The reagent: $$[Ag(NH_3)_2]^+$$ is Tollens' reagent (ammoniacal silver nitrate complex). :contentReference[oaicite:0]{index=0}
Step 1: Why diagram matters.
The OCR text does not fully preserve the structural conversion, so exact substrate/product drawing is missing. In structure-based organic questions, reagent selection depends on:

• starting functional group
• carbon skeleton
• oxidation/reduction level
• rearrangement possibility

Hence the reaction image is essential.
Step 2: Use official answer key.
The provided paper marks: $$\boxed{\text{Option (E)}}$$ Therefore accepted reagent is: $$\boxed{[Ag(NH_3)_2]^+}$$
Step 3: About the reagent.
Tollens' reagent is commonly used for:

• oxidation of aldehydes
• silver mirror test
• selective oxidation in some organic transformations

Step 4: Final answer.
Hence correct option is: $$\boxed{\text{(E)}}$$