#39; is aromaticB. The completion of above reaction. Tags and topics: Aldehydes , Ketones and Carboxylic Acids,JEE MAIN,Hydrocarbons,Aromatic Compounds: Preparation & Chemical Properties,JEE Advanced,JEE Mains,NCERT,NEET,Questions With Image, Class 1.">
#39; is aromaticB. The completion of above reaction. Tags and topics: Aldehydes , Ketones and Carboxylic Acids,JEE MAIN,Hydrocarbons,Aromatic Compounds: Preparation & Chemical Properties,JEE Advanced,JEE Mains,NCERT,NEET,Questions With Image, Class 1.">
#39; is aromaticB. The completion of above reaction. Tags and topics: Aldehydes , Ketones and Carboxylic Acids,JEE MAIN,Hydrocarbons,Aromatic Compounds: Preparation & Chemical Properties,JEE Advanced,JEE Mains,NCERT,NEET,Questions With Image, Class 1.">
Correct statements for the given reaction are :
A. Compound '$\mathrm{B}$' is aromatic
B. The completion of above reaction is very slow
C. 'A' shows tautomerism
D. The bond lengths of C-C in compound $B$ are found to be same
Choose the correct answer from the options given below:
B, C and D only
A, C and D only
A, B and D only
A, B and C only
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Step-by-Step Explanation
Step 1: Identify the Statements and What They Mean
The question provides four statements (A, B, C, and D) about a reaction and its products. We need to decide which of these statements are correct:
(A) Compound B is aromatic.
(B) The completion of the reaction is very slow.
(C) Compound A shows tautomerism.
(D) The bond lengths of the C–C bonds in B are all the same.
Step 2: Assess Statement (A) — “Compound B is Aromatic”
An aromatic compound must typically satisfy:
It is cyclic and planar.
It has a conjugated system of $ \pi $-electrons.
It follows Hückel’s rule, having $(4n + 2)$ $ \pi $-electrons.
If B forms a six-membered ring with delocalized $ \pi $-electrons, it would be aromatic. Evidence from typical organic reactions resulting in a stable ring system suggests that B meets this criterion. Therefore, Statement (A) is correct.
Step 3: Assess Statement (B) — “The Reaction is Very Slow”
Reaction rates depend on many factors (e.g., temperature, catalysts, solvent). The given information does not confirm or provide specific data indicating that the reaction is slow. Without direct kinetic or experimental evidence, we cannot conclude Statement (B) is necessarily correct. Hence, we consider (B) unverified.
Step 4: Assess Statement (C) — “Compound A Shows Tautomerism”
Tautomerism (like keto–enol tautomerism) involves the shift of a hydrogen atom and a repositioning of double bonds. If A has a functional group arrangement (e.g., a carbonyl adjacent to an –OH or something similar) that allows this shift, it can exhibit tautomerism. Many precursors to aromatic ring formation undergo tautomeric shifts. Thus, Statement (C) is plausible and considered correct.
Step 5: Assess Statement (D) — “Bond Lengths in B Are All the Same”
A key characteristic of an aromatic ring (for instance, benzene) is the equalization of bond lengths due to resonance. In a fully conjugated, aromatic system, the C–C bonds in the ring are of equal length. Since B is concluded to be aromatic (from Statement A), its ring C–C bond lengths would be equal. So (D) is correct.
Step 6: Final Conclusion
(A) is true.
(B) is not established.
(C) is true.
(D) is true.
The correct statements are A, C, and D.