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CBSE Class 12 · 2017 · Aldehydes Ketones and Carboxylic AcidsLong Answer

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(a) Write the product(s) of the three reactions shown in the figure.
(b) Give simple chemical tests to distinguish between the following pairs of compounds:
i) butanal and butan-2-one
ii) benzoic acid and phenol
Structure (a)(i)
(a)(i)
Structure (a)(ii)
(a)(ii)
Structure (a)(iii)
(a)(iii)

Solution

(a) For each displayed line apply its printed reagent: hydride → alcohol; named oxidant → acid/ketone; condensation partner → the imine-type product — write the three products off the figure.
(b)(i) Butanal reduces Tollens' reagent (silver mirror); butan-2-one does not. (Butan-2-one is instead iodoform-positive.)
(ii) Benzoic acid gives CO effervescence with NaHCO; phenol gives none (and turns neutral FeCl violet).

CBSE Class 12 Board · 2017 · Subjective

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