Haloalkanes react with $KCN$ to form alkyl cyanides as the main product,while $AgCN$ forms isocyanides as the chief product. Explain.

(N/A) $KCN$ is predominantly ionic and provides cyanide ions $(CN^-)$ in solution. Since the $C-C$ bond is more stable than the $C-N$ bond,the attack occurs mainly through the carbon atom,leading to the formation of alkyl cyanides $(R-CN)$.
Conversely,$AgCN$ is mainly covalent in nature. In this case,the carbon atom is involved in the bond with silver,leaving the nitrogen atom free to donate its lone pair of electrons to the alkyl group,resulting in the formation of isocyanides $(R-NC)$ as the major product.