Question

$Et-\stackrel{O}{\stackrel{||}{C}}-Cl\underset{H_{2}O}{\overset{DIBAL-H}{\to }}\left(X\right)$

$Ph-C\equiv N\underset{ii.H_3{O}^{+}}{\overset{i.SnC{l}_2+HCl}{\to }}\left(Y\right)$

(X) and (Y) can be differnetiated by:

• A. Tollens' reagent
• B. 2,4-DNP test
• C. Fehling solution
• D. Lucas reagent

Answer 1

The correct option is C Fehling solution


$Et-\stackrel{O}{\stackrel{||}{C}}-Cl\underset{H_{2}O}{\overset{DIBAL-H}{\to }}\underset{\left(X\right)}{Et-\stackrel{O}{\stackrel{||}{C}}-H}$

$Ph-C\equiv N\underset{ii.H_3{O}^{+}}{\overset{i.SnC{l}_2+HCl}{\to }}\underset{\left(Y\right)}{Ph-\stackrel{O}{\stackrel{||}{C}}-H}$

(X) and (Y) are propionaldehyde and benzaldehyde respectively.
However, benzaldehyde does not respond to Fehling reagent hence (X) and (Y) can be differentiated by Fehling solution.

Both Tollens' reagent test and 2,4-DNP test will be answered by both aliphatic and aromatic aldehydes.

Aldehydes do not answer Lucas test. It is a test to distinguish primary, secondary and tertiary alcohols.