How will you convert:

Ethanoic acid into propanoic acid

Explanation: To convert ethanoic acid into propanoic acid (the number of carbon atoms are increasing from two carbon atoms to three carbon atoms), we need propionitrile (CH3CH2CN) and we can get propionitrile from ethyl chloride. To get ethyl chloride, we need ethanol which can be formed by the reduction of ethanoic acid.

Step 1: Convert ethanoic acid into ethanol by reduction

Ethanoic acid (CH3COOH ) undergoes reduction in the presence of lithium aluminium hydride (LiAlH4) to form ethanol (CH3CH2OH)

Step 2: Convert ethanol into ethyl chloride

Ethanol (CH3CH2OH ) reacts with PCl5 to form ethyl chloride (CH3CH2Cl) by the replacement of OH group by Cl atom.

Step 3: Convert ethyl chloride into ethyl cyanide/ propionitrile

Ethyl chloride (CH3CH2Cl) reacts with ethanolic NaCN / KCN to give ethyl cyanide/ propionitrile (CH3CH2CN)

Step 4: Convert ethyl cyanide/ propionitrile into propanoic acid

Ethyl cyanide (CH3CH2CN) undergoes hydrolysis to form a propanoic acid (CH3CH2COOH-final product) which has one carbon atom more than the propionitrile.