Review the key concepts, formulae, and examples before starting your quiz.
πConcepts
Alkyl Cyanides (Alkanenitriles) are organic compounds with the general formula . They are functional isomers of Alkyl Isocyanides ().
Cyanide ion () is an ambident nucleophile. Reaction of alkyl halides with alcoholic yields alkyl cyanides because of the ionic nature of , while reaction with yields alkyl isocyanides due to the covalent nature of bond.
The Mendius Reaction involves the reduction of alkyl cyanides with sodium and ethanol to produce primary amines: .
Partial hydrolysis of cyanides with cold conc. or alkaline yields amides (), while complete hydrolysis with boiling dilute acids or alkalies yields carboxylic acids ().
Alkyl isocyanides, upon reduction with or , produce secondary amines containing a methyl group ().
The Carbylamine Reaction is a test for primary amines where they react with chloroform () and alcoholic to form foul-smelling alkyl isocyanides ().
Hydrolysis of isocyanides with dilute acids yields primary amines and formic acid (); notably, isocyanides are not hydrolyzed by alkalies.
πFormulae
π‘Examples
Problem 1:
How will you convert Methyl chloride () to Ethanoic acid ()?
Solution:
Explanation:
Methyl chloride reacts with alcoholic via nucleophilic substitution to form Methyl cyanide (). Complete acid hydrolysis of the cyanide group converts it into a carboxylic acid group, increasing the chain length by one carbon.
Problem 2:
Identify the products and : and .
Solution:
(Ethyl methyl amine), (Ethylamine) + (Formic acid).
Explanation:
Reduction of an isocyanide () adds hydrogen across the functional group to form a amine. Acid hydrolysis of an isocyanide breaks the bond to yield a amine and formic acid.
Problem 3:
Why do alkyl cyanides have higher boiling points than the corresponding alkyl halides?
Solution:
Due to the presence of the polar group, cyanides possess strong intermolecular dipole-dipole interactions.
Explanation:
The large dipole moment of the cyanide group () leads to stronger associations between molecules compared to the weaker dipole-dipole forces in alkyl halides ().