JEE Advanced · Chemistry · 24. Haloalkanes & Haloarenes

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The reaction of compound $\mathbf{P}$ with $\mathrm{CH}_{3} \mathrm{MgBr}$ (excess) in $\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{O}$ followed by addition of $\mathrm{H}_{2} \mathrm{O}$ gives $\mathbf{Q}$. The compound $\mathbf{Q}$ on treatment with $\mathrm{H}_{2} \mathrm{SO}_{4}$ at $0^{\circ} \mathrm{C}$ gives $\mathbf{R}$. The reaction of $\mathbf{R}$ with $\mathrm{CH}_{3} \mathrm{COCl}$ in the presence of anhydrous $\mathrm{AlCl}_{3}$ in $\mathrm{CH}_{2} \mathrm{Cl}_{2}$ followed by treatment with $\mathrm{H}_{2} \mathrm{O}$ produces compound $\mathbf{S}$. [Et in compound $\mathbf{P}$ is ethyl group]

Question :
The reactions, $\mathbf{Q}$ to $\mathbf{R}$ and $\mathbf{R}$ to $\mathbf{S}$, are

A Dehydration and Friedel-Crafts acylation
B Friedel-Crafts alkylation, dehydration, and Friedel-Crafts acylation
C Aromatic sulfonation and Friedel-Crafts acylation
D Friedel-Crafts alkylation and Friedel-Crafts acylation

Verified Solution

Answer & Solution

Correct Answer

(D) Friedel-Crafts alkylation and Friedel-Crafts acylation

Step-by-step Solution

Detailed explanation

The reaction of an ester (other than format) with Grignard’s reagent followed by hydrolysis in acidic medium produces a tertiary alcohol.

The dehydration of

3^{o}

-alcohol at

O^{o} C

in the given compound produces an alkyl group in the benzene ring. This compound on reaction with

{CH}_{3} {COCl}_{2}

{CH}_{2} {Cl}_{2}

and shows Friedel craft's alkylation reaction

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

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Match List-I with List - II and select the correct answer using the code given below the lists

	List-I		List-II
A.	Volume of parallelepiped determined by vectors $\vec{a}, \vec{b}$ and $\vec{c}$ is $2$ . Then the volume of the parallelepiped determined by vectors $2 (\vec{a} \times \vec{b}), 3 (\vec{b} \times \vec{c})$ and $(\vec{c} \times \vec{a})$ is	P.	$100$
B.	Volume of parallel piped determined by vectors $\vec{a}, \vec{b}$ and $\vec{c}$ is $5$ . Then the volume of the parallelepiped determined by vectors $3 (\vec{a} + \vec{b}), (\vec{b} + \vec{c})$ and $2 (\vec{c} + \vec{a})$ is	Q.	$30$
C	Area of a triangle with adjacent sides determined by vectors $\vec{a}$ and $\vec{b}$ is $20$ .Then the area of the triangle with adjacent sides determined by vectors $(2 \vec{a} + 3 \vec{b})$ and $(\vec{a} - \vec{b})$ is	R.	$24$
D	Area of a parallelogram with adjacent sides determined by vectors $\vec{a}$ and $\vec{b}$ is $30$ . Then the area of the parallelogram with adjacent sides determined by vectors $(\vec{a} + \vec{b})$ and $\vec{a}$ is	S.	$60$

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Exp. No.	Vol. of NaOH (mL)
1	12.5
2	10.5
3	9.0
4	9.0
5	9.0