Question

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

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

Answer 1

The Correct Option is A

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).

Answer 2

Step 1: Given reaction sequence.
The sequence of reactions is:
CH₃CH₂OH → (i) Jones reagent → (ii) KMnO₄ → (iii) NaOH, CaO, Δ

Step 2: Step-by-step reaction process.
(i) Oxidation with Jones reagent (CrO₃ + H₂SO₄):
Ethanol (CH₃CH₂OH) is oxidized to ethanoic acid (CH₃COOH).
\[ CH₃CH₂OH \xrightarrow[\text{H₂SO₄}]{CrO₃} CH₃COOH \]

(ii) Oxidation with KMnO₄:
No further oxidation occurs because ethanoic acid (CH₃COOH) is already at its highest oxidation state for carbon in that molecule.
So, the product remains CH₃COOH.

(iii) Decarboxylation (NaOH, CaO, Δ):
This step is soda lime decarboxylation, which removes the –COOH group as CO₂ and replaces it with a hydrogen atom.
\[ CH₃COOH \xrightarrow[\Delta]{NaOH,\,CaO} CH₄ \]
Hence, the final product formed is **methane (CH₄).**

Step 3: Final Answer.
The major product P is:
\[ \boxed{\text{Methane}} \]

Final Answer: Methane