Identify X in the following reaction. p-Br-C6H4-Cl (1.0 mol) ->[Mg (1.0 mol)][dry ether] Intermediate ->[D2O] X

Correct answer: (C) (C) p-Cl-C6H4-D. The C-Br bond is weaker and more reactive than C-Cl, so with only 1 mol Mg the Grignard forms chemoselectively at the bromine end: p-Br-C6H4-Cl ->[Mg][dry ether] p-ClC6H4-MgBr. The C-Cl bond is untouched. D2O then protonates (deuterates) the C-Mg carbon: p-ClC6H4-MgBr + D2O -> p-Cl-C6H4-D + Mg(OD)Br, giving 4-deuteriochlorobenzene.

NEET 2023 Phase 2 · ChemistryPrevious Year Question

Identify $X$ in the following reaction. $p - Br - C X_{6} H X_{4} - Cl$ (1.0 mol) $Mg (1.0 mol) dry ether$ Intermediate $D X_{2} O$ $X$

Answer: (C) (C) $p - Cl - C X_{6} H X_{4} - D$ . The $C - Br$ bond is weaker and more reactive than $C - Cl$ , so with only 1 mol Mg the Grignard forms chemoselectively at the bromine end: $p - Br - C X_{6} H X_{4} - Cl Mg dry ether p - ClC X_{6} H X_{4} - MgBr$ .

A.(A) $p - D - C X_{6} H X_{4} - D$
B.(B) $p - D - C X_{6} H X_{4} - Br$
C.(C) $p - Cl - C X_{6} H X_{4} - D$ ✓
D.(D) $p - DO - C X_{6} H X_{4} - OD$

Correct Answer

Solution & Explanation

The $C - Br$ bond is weaker and more reactive than $C - Cl$ , so with only 1 mol Mg the Grignard forms chemoselectively at the bromine end: $p - Br - C X_{6} H X_{4} - Cl Mg dry ether p - ClC X_{6} H X_{4} - MgBr$ . The $C - Cl$ bond is untouched. $D X_{2} O$ then protonates (deuterates) the $C - Mg$ carbon: $p - ClC X_{6} H X_{4} - MgBr + D X_{2} O p - Cl - C X_{6} H X_{4} - D + Mg (OD) Br$ , giving 4-deuteriochlorobenzene.

🎯

43,000+ questions in हिंदी & English · one-tap toggle

Practice NEET 2023 Phase 2 Chemistry — free, with instant solutions

43,000+ NEET questions solved step-by-step, chapter-wise, in the MedicNEET app.

Open →📚Practice all NEET Chemistry PYQs chapter-wise →💡Don't get it? Learn the Haloalkanes And Haloarenes concepts →

← Chemistry Q12 Chemistry Q14 →

More NEET PYQ solutions

ChemIdentify the suitable reagent for the following conversion: C6H5COOCH3 -> C6H5CHO (methyl benzoate to benzaldehyde)ChemThe correct order of decreasing acidity of the following aliphatic acids is ChemThe major product of the following reaction is: 4-oxo-4-phenylbutanenitrile C6H5-CO-CH2-CH2-CN is treated with (i) CH3MgBr (excess) and then (ii) H3O+.ChemOut of the following complex compounds, which compound will have the minimum conductance in solution?ChemWhich of the following are paramagnetic? A. [NiCl4]^2- B. Ni(CO)4 C. [Ni(CN)4]^2- D. [Ni(H2O)6]^2+ E. Ni(PPh3)4 ChemThe correct order of the wavelength of light absorbed by the following complexes is: A. [Co(NH3)6]^3+ B. [Co(CN)6]^3- C. [Cu(H2O)4]^2+ D. [Ti(H2O)6]^3+ChemThe correct order of decreasing basic strength of the given amines is: (N-ethylethanamine = (C2H5)2NH; ethanamine = C2H5NH2; N-methylaniline = C6H5NH(CH3); benzenamine/aniline = C6H5NH2)ChemPredict the major product P in the following sequence of reactions. The starting material is 1-methylcyclopent-1-ene: (i) HBr, benzoyl peroxide; (ii) KCN; (iii) Na(Hg)/C2H5OH P (major). The structures of the options (A)-(D) are shown in the image below:

More: All NEET 2023 Phase 2 Chemistry PYQs · NEET Chemistry PYQs · All NEET PYQs · Previous year papers

Identify X in the following reaction. p-Br-CX6​HX4​-Cl (1.0 mol) Mg (1.0 mol)dry ether​ Intermediate DX2​O​ X

Solution & Explanation

More NEET PYQ solutions

Identify $X$ in the following reaction. $p - Br - C X_{6} H X_{4} - Cl$ (1.0 mol) $Mg (1.0 mol) dry ether$ Intermediate $D X_{2} O$ $X$