How would you distinguish between product P and Q formed in the reaction given below?

Correct Option: Iodoform test

Step-by-step Explanation:

1. Analysis of the Reactant and Reaction Conditions:
The image shows an unsymmetrical di-alkenyl ether: 1-(vinyloxy)prop-1-ene (${\mathrm{CH}}_3-\mathrm{CH}=\mathrm{CH}-O-\mathrm{CH}={\mathrm{CH}}_2$). It contains two distinct enol ether halves attached to the central oxygen atom:
• A prop-1-enyl group (${\mathrm{CH}}_3-\mathrm{CH}=\mathrm{CH}-$) on the left.
• A vinyl (ethenyl) group ($-\mathrm{CH}={\mathrm{CH}}_2$) on the right.
The reaction is carried out in the presence of hydronium ions ($H_3{O}^{+}$) and heat ($\Delta$), which leads to acid-catalyzed hydrolysis of both enol ether functions.

2. Identification of Products P and Q:
Under acidic conditions, enol ethers undergo protonation followed by nucleophilic attack by water, resulting in C-O bond cleavage to form enols, which rapidly tautomerize to their more stable carbonyl forms:
• Hydrolysis of the prop-1-enyl ether group gives prop-1-en-1-ol:
${\mathrm{CH}}_3-\mathrm{CH}=\mathrm{CH}-\mathrm{OH}$
This tautomerizes to propanal (Product P):
${\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{CHO}$

• Hydrolysis of the vinyl ether group gives vinyl alcohol (ethenol):
${\mathrm{CH}}_2=\mathrm{CH}-\mathrm{OH}$
This tautomerizes to ethanal (acetaldehyde, Product Q):
${\mathrm{CH}}_3-\mathrm{CHO}$

3. Distinguishing Between P and Q:
To distinguish between propanal (${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{CHO}$) and ethanal (${\mathrm{CH}}_3\mathrm{CHO}$), let us evaluate the given chemical tests:
• Fehling's solution test & Tollens' test: Both propanal and ethanal are aliphatic aldehydes and will give positive results for both of these tests (forming a red precipitate of ${\mathrm{Cu}}_{2}O$ and a silver mirror, respectively). Thus, these tests cannot distinguish between them.
• 2,4-DNP test: Both compounds are carbonyl compounds and react with 2,4-dinitrophenylhydrazine to form yellow-orange precipitates. Thus, this test also cannot distinguish between them.
• Iodoform test: The iodoform test ($I_2/\mathrm{NaOH}$) specifically identifies compounds containing a methyl carbonyl group (${\mathrm{CH}}_3-\mathrm{CO}-$). Ethanal (${\mathrm{CH}}_3-\mathrm{CHO}$) has a methyl group directly bonded to the carbonyl carbon and yields a yellow precipitate of iodoform (${\mathrm{CHI}}_3$):
${\mathrm{CH}}_3\mathrm{CHO}+3I_2+4\mathrm{NaOH}\to {\mathrm{CHI}}_3\downarrow +\mathrm{HCOONa}+3\mathrm{NaI}+3H_{2}O$
Propanal (${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{CHO}$) does not have a ${\mathrm{CH}}_3-\mathrm{CO}-$ group and does not react. Therefore, the Iodoform test is the correct method to distinguish them.