Question

Consider the above reaction sequence and identify the major product P.

• A. Methane
• B. Methanal
• C. Methoxymethane
• D. Methanoic acid

Answer 1

Answer: (A)

Methane

Answer 2

The reaction sequence is as follows:
Step 1: Oxidation using Jones Reagent
Jones reagent ($\text{CrO}_3 + \text{H}_2\text{SO}_4$) oxidizes primary alcohols ($\text{CH}_3\text{CH}_2\text{OH}$) to carboxylic acids. Ethanol ($\text{CH}_3\text{CH}_2\text{OH}$) is oxidized to acetic acid ($\text{CH}_3\text{COOH}$).
$\text{CH}_3\text{CH}_2\text{OH} \rightarrow [\text{JonesReagent}] \text{CH}_3\text{COOH}.$
Step 2: Oxidation using $\text{KMnO}_4$
The acetic acid ($\text{CH}_3\text{COOH}$) is further oxidized to carbonic acid ($\text{H}_2\text{CO}_3$) by $\text{KMnO}_4$. Carbonic acid is unstable and decomposes to $\text{CO}_2$ and water.
$\text{CH}_3\text{COOH} \rightarrow [\text{KMnO}_4]\text{H}_2\text{CO}_3 \rightarrow \text{CO}_2 + \text{H}_2\text{O}.$
Step 3: Decarboxylation using Soda Lime
The carbon dioxide ($\text{CO}_2$) reacts with soda lime ($\text{NaOH} + \text{CaO}$) to form methane ($\text{CH}_4$) via decarboxylation.
$\text{CO}_2 + \text{NaOH} \rightarrow \text{CH}_4 + \text{Na}_2\text{CO}_3.$
Final Product:
The major product $P$ is methane ($\text{CH}_4$).
Final Answer: (1).