Identify the A and B in the following reactions in alcoholic...

KCN is predominantly ionic and provides cyanide ions in solution. The attack takes place mainly through the carbon atom since the C-C bond is more stable than the C-N bond. Thus, KCN gives alkyl cyanides (RCN) as the major product.

AgCN is mainly covalent in nature and nitrogen is free to donate an electron pair forming an isocyanide as the main product. Thus, AgCN gives alkyl isocyanides (RNC) as the major product.

Therefore, A is RNC and B is RCN.

Answer: $\text{A} \rightarrow \text{RNC}; \text{B} \rightarrow \text{RCN}$