• Students should be able to critically analyse given synthetic routes and determine whether appropriate reagents and reaction conditions are used
• Students should also be able to predict possible by-product of a synthetic reaction

Worked Example: Two-step synthesis

Answer

The correct answer is??D

The first step involves a nucleophilic addition of CN-?using NaCN as catalyst and heat to form a hydroxynitrile.

In the second step, the nitrile is refluxed with dilute aqueous sulfuric acid causing hydrolysis of the nitrile forming a carboxylic acid and ammonium salt.

Worked Example: Synthesis of hexanoic acid

Answer

The correct answer is?C

Halogenoalkanes can undergo?nucleophilic substitution?with ethanolic KCN in which the CN-?ion acts as a nucleophile and replaces the chlorine atom in 1-chloropentane to form a?nitrile.

The treatment of nitriles with concentrated hydrochloric acid will produce a carboxylic acid and an ammonium salt.

In this case, hexanoic acid and ammonium chloride will be formed.