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Question: Which of the following compounds will give acetic acid with \(KMn{O_4}/H/\Delta \). A. \(C{H_3} - ...

Which of the following compounds will give acetic acid with KMnO4/H/ΔKMn{O_4}/H/\Delta .
A. CH3−CHOC{H_3} - CHO
B. CH3−CH=CH−CH3C{H_3} - CH = CH - C{H_3}
C. CH3−C≡C−CH3C{H_3} - C \equiv C - C{H_3}
D. CH3CH2OHC{H_3}C{H_2}OH

Explanation

Solution

Acetic acid also known as ethanoic acid is the most important among the carboxylic acids. Moreover, KMnO4KMn{O_4} acts as an oxidizing agent in this reaction. It is considered as a strong oxidizing agent and is usually prepared from other minerals such as manganese.

Complete step by step answer:
When ethanol is oxidized with alkaline potassium permanganate, it gets oxidized to form ethanoic acid.
CH3CH2OH+2[O]→Alkaline KMnO4CH3COOH+H2OC{H_3}C{H_2}OH + 2[O]\xrightarrow{{Alkaline\,KMn{O_4}}}C{H_3}COOH + {H_2}O
KMnO4KMn{O_4}is an oxidizing agent so it will convert the aldehyde group into acid.
CH3CHO→KMnO4ΔCH3−COOHC{H_3}CHO\xrightarrow[{KMn{O_4}}]{\Delta }C{H_3} - COOH
Ethanol is further oxidized to acetaldehyde on treatment with acidified potassium permanganate. Afterwards, acetaldehyde further gets oxidized to acetic acid.
The acidified potassium permanganate also breaks the carbon-carbon double and triple bonds. The two carbons attached to multiple bonds are oxidized to carboxylic acid.
Now, let’s consider the reaction with alkene,
CH3−CH=CH−CH3→KMnO42CH3COOHC{H_3} - CH = CH - C{H_3}\xrightarrow[{}]{{KMn{O_4}}}2C{H_3}COOH
The product formed is acetic acid.
Now, in the last case also i.e. in case of alkynes, the product formed is acetic acid. The reaction is as shown:
CH3−C≡C−CH3→KMnO42CH3COOHC{H_3} - C \equiv C - C{H_3}\xrightarrow{{KMn{O_4}}}2C{H_3}COOH
Hence, all the four options on oxidation with acidified potassium permanganate gives acetic acid.
Moreover, when a solution of ethyl alcohol and alkaline KMnO4KMn{O_4} is heated, the pink color of the solution disappears. Since, KMnO4KMn{O_4} is a strong oxidizing agent, it oxidizes ethanol to ethanoic acid by donating nascent oxygen,

Hence, all the options are correct.

Note:
Potassium permanganate is used in qualitative analysis to determine the permanganate value. It is also used as a regeneration chemical in well water treatment for the removal of hydrogen sulphide and iron. This compound is also used as a disinfectant to cure certain skin conditions like foot fungal infections, dermatitis etc. This compound can even be used as a bleaching agent, as a pesticide and as an antiseptic.