# Reaction of alkyl halides with potassium cyanide

Its given in my book that alkyl halides react with alcoholic potassium cyanide to give alkyl cyanide through $$\mathrm{S_N2}$$ mechanism.

But why do we need to use alcoholic $$\ce{KCN}$$ (potassium cyanide dissolved in alcohol)? My understanding is that polar protic solvent favours $$\mathrm{S_N1}$$ over $$\mathrm{S_N2}.$$

• Solubility. Potassium cyanide does not dissolve in non-polar aprotics – Waylander Dec 4 '19 at 15:38
• Does alcohol have any role in reaction. Can we have reaction using only KCN – Grace Dec 4 '19 at 15:44
• As @Waylander said, alcohol does not participate in the reaction itself. It only dissolves KCN so that it can dissociate to give the $\ce{CN-}$ nucleophile – Aniruddha Deb Dec 4 '19 at 15:58
• Then instead of alcoholic can we use aqueous KCN – Grace Dec 4 '19 at 16:30
• No because then the alkyl halide will not be soluble – Raoul Kessels Dec 4 '19 at 16:37