Chemistry - AMINES Question with Solution | TestHub

$\mathrm{R}\mathrm{X}+\mathrm{A}\mathrm{g}\mathrm{C}\mathrm{N}\to \underset{\left(\mathrm{P}\right)}{\mathrm{R}\mathrm{N}\mathrm{C}}+\mathrm{A}\mathrm{g}\mathrm{X}$

$\mathrm{R}\mathrm{X}+\mathrm{K}\mathrm{C}\mathrm{N}\to \underset{\left(\mathrm{Q}\right)}{\mathrm{R}\mathrm{C}\mathrm{N}}+\mathrm{K}\mathrm{X}$

Both C and N can donate electron pairs. Since KCN is predominantly ionic and$\mathrm{C}-\mathrm{C}$bond is more stable than$\mathrm{C}-\mathrm{N}$bond in case of KCN, attack takes place through carbon atom.

AgCN is predominantly covalent hence only nitrogen pair is available for bonding resulting in formation of isocyanide.