CBSE 2024 · Region 5 · Set 2 · Q31 · 5 marks
An organic compound (A) with the molecular formula $\displaystyle \mathrm{C}_{9} \mathrm{H}_{10} \mathrm{O}$ forms $\displaystyle 2$, $\displaystyle 4$-DNP derivative, reduces Fehling solution and undergoes Cannizzaro reaction. On vigorous oxidation, it gives $\displaystyle 1$, $\displaystyle 2$-benzene dicarboxylic acid.(i)Identify the compound (A) and write its IUPAC name.(ii)Write the reaction of compound (A) with(1)$\displaystyle 2$, $\displaystyle 4$-Dinitrophenyl hydrazine and(2)Fehling solution(iii)Write the equation of compound (A) when it undergoes Cannizzaro reaction. $\displaystyle \mathbf{2}+\mathbf{2}+\mathbf{1}$(b)Account for the following :(1)The alpha ( $\displaystyle \alpha$ )-hydrogens of aldehydes and ketones are acidic in nature.(2)Oxidation of aldehydes is easier than ketones.(ii)Arrange the following in :(1)Decreasing reactivity towards nucleophilic addition reaction propanal, acetone, benzaldehyde.(2)Increasing order of boiling point : Propane, Ethanol, Dimethylether, Propanal(iii)Give simple chemical test to distinguish between Benzoic acid and Benzaldehyde.
An organic compound (A) with the molecular formula $\displaystyle \mathrm{C}_{9} \mathrm{H}_{10} \mathrm{O}$ forms $\displaystyle 2$, $\displaystyle 4$-DNP derivative, reduces Fehling solution and undergoes Cannizzaro reaction. On vigorous oxidation, it gives $\displaystyle 1$, $\displaystyle 2$-benzene dicarboxylic acid.
(i)
Identify the compound (A) and write its IUPAC name.
(ii)
Write the reaction of compound (A) with
(1)
$\displaystyle 2$, $\displaystyle 4$-Dinitrophenyl hydrazine and
(2)
Fehling solution
(iii)
Write the equation of compound (A) when it undergoes Cannizzaro reaction. $\displaystyle \mathbf{2}+\mathbf{2}+\mathbf{1}$
(b)
Account for the following :
(1)
The alpha ( $\displaystyle \alpha$ )-hydrogens of aldehydes and ketones are acidic in nature.
(2)
Oxidation of aldehydes is easier than ketones.
(ii)
Arrange the following in :
(1)
Decreasing reactivity towards nucleophilic addition reaction propanal, acetone, benzaldehyde.
(2)
Increasing order of boiling point : Propane, Ethanol, Dimethylether, Propanal
(iii)
Give simple chemical test to distinguish between Benzoic acid and Benzaldehyde.
Marking-scheme solution
(i)
<smiles>CCC1C=CC=CC1C=O</smiles>
$\displaystyle 2$ - Ethylbenzaldehyde
(A)
ii)
<smiles>CCc1ccccc1C=NN=Cc1ccccc1[N+](=O)[O-]</smiles>
(2)
Aromatic aldehydes do not give fehling'stest ,$\displaystyle 1$ mark to be given if attempted in any way.
Aldehydes, Ketones and Carboxylic AcidsChemical Reactions of Aldehydes, Ketones and Carboxylic AcidsAnalyselong_answermedium
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