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CBSE Class 12 · 2022 · Aldehydes Ketones and Carboxylic AcidsShort Answer

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a) Complete the following:
i) CH₃CN →1. DIBAL-H 2. H₂O→ 'A' →NH₂OH/H⁺→ 'B'
ii) Write the IUPAC name of the compound shown in the figure (3-bromobenzaldehyde).
iii) Write a chemical test to distinguish between phenol and benzoic acid.
Structure (a)(ii): structure to name
(a)(ii): structure to name

Answer: A = CH₃CHO; B = acetaldoxime CH₃CH=NOH. (ii) 3-Bromobenzaldehyde. (iii) NaHCO₃ — effervescence with benzoic acid only.

Solution

(i) DIBAL-H half-reduces the nitrile; hydrolysis gives the aldehyde:

(ii)

(iii) NaHCO: benzoic acid gives brisk CO effervescence; phenol gives none.

CBSE Class 12 Board · 2022 · Subjective

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