Question

Explain the given reaction with examples.
                  Oxidation reaction:
A.${{C}_{2}}{{H}_{5}}OH\xrightarrow{Alk.KMn{{O}_{4}}}C{{H}_{2}}OHCOOH$
B.${{C}_{2}}{{H}_{5}}OH\xrightarrow{Alk.KMn{{O}_{4}}}C{{H}_{3}}C{{H}_{3}}$
C.${{C}_{2}}{{H}_{5}}OH\xrightarrow{Alk.KMn{{O}_{4}}}C{{H}_{3}}C{{H}_{2}}OH$
D.${{C}_{2}}{{H}_{5}}OH\xrightarrow{Alk.KMn{{O}_{4}}}C{{H}_{3}}COOH$

Answer 1

Hint: Before answering this question, we should know what are primary alcohols and their reaction. Primary alcohols are those alcohols in which the hydroxyl group is linked to the primary carbon atom itself. The primary alcohol gets oxidized to carboxylic acids in the presence of oxidants.

Complete answer:
 In Organic chemistry, The oxidation of primary alcohols and getting converted to carboxylic acids is a major oxidation reaction.
PRIMARY ALCOHOLS
Some oxidants that are commonly used are alkaline potassium permanganate $(KMn{{O}_{4}})$or acidified potassium dichromate. Some more are PCC in DMF, Jones reagent, Heyns Oxidation, ruthenium tetroxide, and TEMPO.
The oxidizing agent should be in excess so that aldehyde is formed as the halfway product, then the alcohol is heated and carboxylic acid is distilled off at the end of the reaction.

Therefore, Option (D) ${{C}_{2}}{{H}_{5}}OH\xrightarrow{Alk.KMn{{O}_{4}}}C{{H}_{3}}COOH$ is correct.

Note:
In the case of- SECONDARY ALCOHOLS
In the case of secondary alcohols, they undergo oxidation and get converted to ketones.
For example- if propan-2-ol is oxidized in the presence of potassium dichromate solution with dilute sulphuric acid, the formation of propanone occurs.
TERTIARY ALCOHOLS
In the case of tertiary alcohols, no reaction occurs in the presence of oxidants like acidified potassium dichromate when they undergo oxidation. If we look at the case of the primary alcohols and secondary alcohols, we will see the oxidant will eliminate hydrogen from the -OH group and H from the carbon atom which is linked to -OH. So, In tertiary alcohols, no hydrogen atom is linked to that carbon.
In the reaction, Primary alcohol (Ethanol) undergoes oxidation in the presence of oxidant (Alkaline potassium permanganate$(KMn{{O}_{4}})$ gets converted to Carboxylic acid (Acetic acid).