Considering the following reaction sequence, the correct statement(s) is (are)
Correct Answer :
Compounds P and Q are carboxylic acids
Compounds P and S react with hydroxylamine to give the corresponding oximes.
Solution :
The correct statement(s) are: Compounds P and Q are carboxylic acids and Compounds P and S react with hydroxylamine to give the corresponding oximes.
Let us analyze the step-by-step chemical transformations visible in the reaction sequence image:
Step 1: Formation of Compound P
Benzene reacts with succinic anhydride in the presence of anhydrous (Friedel-Crafts acylation). The succinic anhydride ring opens to form a keto-acid compound:
Compound P: (3-benzoylpropanoic acid).
Compound P contains both a carbonyl ketone group () and a carboxylic acid group ().
Step 2: Formation of Compound Q
Compound P undergoes Clemmensen reduction using amalgam zinc and concentrated hydrochloric acid (). The carbonyl group () is reduced to a methylene group (), while the carboxylic acid group remains unchanged:
Compound Q: (4-phenylbutanoic acid).
Hence, both P and Q contain terminal groups and are carboxylic acids.
Step 3: Formation of Compound R
Reaction of 4-phenylbutanoic acid (Q) with thionyl chloride () converts the carboxylic acid into an acyl chloride:
Compound R: (4-phenylbutanoyl chloride).
Step 4: Formation of Compound S
Treatment of acyl chloride (R) with anhydrous undergoes intramolecular Friedel-Crafts acylation to form a cyclic ketone:
Compound S: -Tetralone (1-tetralone), which contains a carbonyl keto group () fused to the benzene ring.
Now let us evaluate each statement option:
1. Compounds P and Q are carboxylic acids:
As derived, Compound P (3-benzoylpropanoic acid) and Compound Q (4-phenylbutanoic acid) both contain carboxylic acid functionality. (Correct)
2. Compounds P and S react with hydroxylamine to give the corresponding oximes:
Both Compound P and Compound S contain carbonyl keto groups (). Carbonyl compounds react readily with hydroxylamine () to form oximes (). (Correct)
3. Compound S decolorizes bromine water:
Compound S (-tetralone) is a saturated cyclic ketone fused to an aromatic ring. It does not have non-aromatic carbon-carbon double or triple bonds to undergo addition reaction with bromine water. Thus, it does not decolorize bromine water. (Incorrect)
4. Compound R reacts with dialkylcadmium to give the corresponding tertiary alcohol:
Dialkylcadmium () reacts with acyl chlorides (like Compound R) to give ketones, not tertiary alcohols, because dialkylcadmium is not nucleophilic enough to react further with the resulting ketone. (Incorrect)
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