CBSE 2024 · Region 4 · Set 1 · Q25 · 3 marks
(a)Give chemical tests to distinguish between the following pairs of compounds :(i)Phenol and Benzoic acid(ii)Propanal and Propanone(b)Which one of the given compounds is a stronger acid and why ? $\displaystyle \mathrm{CH}_{2} \mathrm{FCH}_{2} \mathrm{CH}_{2} \mathrm{COOH}$ or $\displaystyle \mathrm{CH}_{3} \mathrm{CHFCH}_{2} \mathrm{COOH}$ $\displaystyle 2+1$
(a)
Give chemical tests to distinguish between the following pairs of compounds :
(i)
Phenol and Benzoic acid
(ii)
Propanal and Propanone
(b)
Which one of the given compounds is a stronger acid and why ? $\displaystyle \mathrm{CH}_{2} \mathrm{FCH}_{2} \mathrm{CH}_{2} \mathrm{COOH}$ or $\displaystyle \mathrm{CH}_{3} \mathrm{CHFCH}_{2} \mathrm{COOH}$ $\displaystyle 2+1$
Marking-scheme solution
(i)
On adding neutral \(\displaystyle \mathrm{FeCl}_{3}\), phenol gives violet colouration whereasbenzoic acid does not give violet colour.
(ii)
On adding Tollens reagent, propanal gives silver mirror whereas propanone does not. .
(b)
\(\displaystyle \mathrm{CH}_{3} \mathrm{CHF} \mathrm{CH}_{2} \mathrm{COOH}\); due to stronger - I effect or electron withdrawing nature of F, as F is closer to the carboxyl group.
Aldehydes, Ketones and Carboxylic AcidsChemical Reactions of Aldehydes, Ketones and Carboxylic AcidsApplyshort_answermedium
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CBSE Class 12 Chemistry past-paper question from the 2024board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.