Question

Identify reagent B in following reaction.
\(\text{R}-\text{X}\overset{\text{B} \,}{\rightarrow }\text{Nitroalkane}\)

• A. \(\text{Ag}-\text{O}-\text{N} = \text{O}\)
• B. \(\text{NaOR}\)
• C. \(\text{KCN (alc.)}\)
• D. \(\text{K}-\text{O}-\text{N} = \text{O}\)

Hint:

Silver nitrite (AgNO2) is covalent and attacks through nitrogen to give nitroalkane.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The nitrite ion, \(\text{NO}_2^-\), is an ambident nucleophile: it can attack through N or through O.

Step 2: Silver Nitrite:
\(\text{AgNO}_2\) is largely covalent, so the nitrogen lone pair is free for attack. The product is a nitroalkane, \(\text{R-NO}_2\).
\[ \text{R-X} + \text{AgNO}_2 \rightarrow \text{R-NO}_2 + \text{AgX} \]

Step 3: Check the Other Options:
\(\text{KNO}_2\) is ionic and attacks through oxygen, which gives alkyl nitrite \(\text{R-O-N=O}\). \(\text{NaOR}\) gives an ether and alcoholic KCN gives a nitrile. Option (A) is the reagent that gives the nitro compound. Option (A), \(\text{Ag-O-N=O}\), is the written form of silver nitrite.

Final Answer:
Silver nitrite gives the nitroalkane, option (A). \[ \boxed{\text{(A) AgNO}_2} \]