CBSE 2023 · Region 4 · Set 3 · Q34 · 5 marks
(a)Draw structure of the $\displaystyle 2,4$-dinitrophenylhydrazone of benzaldehyde.(b)Which acid of the following pair is a stronger acid ?
or
(c) Write the chemical equation involved in Rosenmund's reduction.(d)Why are $\displaystyle \alpha$-hydrogen atoms of aldehydes and ketones acidic in nature?(e)Write a chemical test to distinguish between Benzaldehyde and Benzoic acid.
(a)
Draw structure of the $\displaystyle 2,4$-dinitrophenylhydrazone of benzaldehyde.
(b)
Which acid of the following pair is a stronger acid ?
or
(c) Write the chemical equation involved in Rosenmund's reduction.
(d)
Why are $\displaystyle \alpha$-hydrogen atoms of aldehydes and ketones acidic in nature?
(e)
Write a chemical test to distinguish between Benzaldehyde and Benzoic acid.
Marking-scheme solution
(a) <smiles>O=[N+]([O-])c1ccc(NC=Nc2ccccc2)c([N+](=O)[O-])c1</smiles>
(b) <smiles>O=C(O)c1ccc(C(F)(F)F)cc1</smiles>
(c)
(d) Due to resonance stabilization of conjugate base enolate ion.
(e) On adding \(\displaystyle \mathrm{NaHCO}_{3}\) solution, Benzoic acid gives effervescence of \(\displaystyle \mathrm{CO}_{2}\) whereas Benzaldehyde does not.
Aldehydes, Ketones and Carboxylic AcidsChemical Reactions of Aldehydes, Ketones and Carboxylic AcidsApplylong_answermedium
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CBSE Class 12 Chemistry past-paper question from the 2023board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.