(a) An organic compound (A) with the molecular formula C₉H₁₀O forms a 2,4-DNP derivative, reduces Fehling solution and undergoes Cannizzaro reaction. On vigorous oxidation it gives benzene-1,2-dicarboxylic acid.
(i) Identify compound (A) and write its IUPAC name.
(ii) Write the reaction of compound (A) with (1) 2,4-dinitrophenylhydrazine and (2) Fehling solution.
(iii) Write the equation for compound (A) undergoing the Cannizzaro reaction.
(i) Identify compound (A) and write its IUPAC name.
(ii) Write the reaction of compound (A) with (1) 2,4-dinitrophenylhydrazine and (2) Fehling solution.
(iii) Write the equation for compound (A) undergoing the Cannizzaro reaction.
Answer: A = 2-ethylbenzaldehyde (o-C₂H₅–C₆H₄–CHO).
Solution
2,4-DNP + Fehling ⇒ an (aliphatic-behaving) aldehyde; Cannizzaro ⇒ no α-H on the CHO carbon ⇒ aromatic CHO; oxidation → benzene-1,2-dicarboxylic acid ⇒ an ortho CH side chain.
(i)
(ii)(1) A + 2,4-DNP → the orange 2,4-dinitrophenylhydrazone, o-CHCHCH=N–NH–CH(NO) + HO.
(2) A + 2Cu (Fehling) + 5OH → o-CHCHCOO + CuO↓(red) + 3HO.
(iii)
(Note: this aromatic aldehyde's Fehling behaviour is as the paper states.)
(i)
(ii)(1) A + 2,4-DNP → the orange 2,4-dinitrophenylhydrazone, o-CHCHCH=N–NH–CH(NO) + HO.
(2) A + 2Cu (Fehling) + 5OH → o-CHCHCOO + CuO↓(red) + 3HO.
(iii)
(Note: this aromatic aldehyde's Fehling behaviour is as the paper states.)
CBSE Class 12 Board · 2024 · Subjective