Question

Observe the following reaction and same reaction is carried out with the following compound: 

X and Y can be differentiated by: 
 

• A. Fehling’s test
• B. 2,4-DNP
• C. NaHSO$_3$
• D. Lucas test

Hint:

Fehling’s test is specific for aliphatic aldehydes and does not react with ketones.

Answer 1

The Correct Option is A

To differentiate between compounds X and Y in the given reaction, we need to apply various chemical tests and determine which test will effectively distinguish between the two. Here are the options considered:

1. Fehling’s Test:
   • Fehling's test is used to detect the presence of aldehydes. Aldehydes reduce Fehling’s solution, turning it from blue to a brick-red precipitate.
   • If X or Y is an aldehyde, it will give a positive Fehling’s test.
   • From the reaction, it appears X forms an aldehyde group, therefore Fehling's test can differentiate them.
2. 2,4-DNP Test:
   • 2,4-Dinitrophenylhydrazine reacts with carbonyl groups (both aldehydes and ketones) to form yellow/orange precipitates.
   • This test will not differentiate between aldehydes and ketones because both give positive results.
3. NaHSO₃ Test:
   • This test is for carbonyl compounds, primarily aldehydes and some ketones, but it's not specific for distinguishing between them.
4. Lucas Test:
   • Lucas test is used to differentiate between primary, secondary, and tertiary alcohols based on the rate of turbidity formation.
   • This test is inappropriate as it doesn’t involve alcohols in the given reaction.

Conclusion: Based on the ability to identify the aldehyde group specifically, Fehling’s test is suitable for differentiating between X and Y.