Which from following reagents is used to prepare alkyl isocyanides from RX?

Step-by-step solution

Alkyl halides react with alcoholic silver cyanide ( AgCN ) to form alkyl isocyanides as the major product. AgCN is predominantly covalent in nature, so only the nitrogen atom has a lone pair of electrons available for nucleophilic attack. This leads to the formation of an alkyl isocyanide ( RNC ). R-X + AgCN R-NC + AgX In contrast, KCN gives alkyl cyanides, KNO ₂ gives alkyl nitrites, and AgNO ₂ gives nitroalkanes. Answer: AgCN (alco)