Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Advanced2026ChemistryHydrocarbonsActual

Treatment of buta-1,3-diyne with NaNH ₂ ( 2 equivalents), followed by reaction with excess of trans - CH ₃ -CH=CH-CH ₂ -Br gives X as the major product. The maximum number of carbon atoms that are collinear (in a straight line) in X is ____.

Correct answer

0

Step-by-step solution

Buta-1,3-diyne ( HC C - C CH ) reacts with 2 equivalents of NaNH ₂ to undergo double deprotonation, forming the acetylide dianion: HC C - C CH + 2 NaNH ₂ ^ C C - C C ^ + 2 NH ₃ This dianion acts as a strong nucleophile and undergoes an S_N2 reaction with the primary allylic halide, trans - CH ₃ -CH=CH-CH ₂ -Br (excess ensures both sides react): ^ C C - C C ^ + 2 CH ₃ -CH=CH-CH ₂ -Br CH ₃ -CH=CH-CH ₂ - C C - C C - CH ₂ -CH=CH-CH ₃ In the major product X , the central diyne unit consists of four sp hybridized carbon

Practice Hydrocarbons on Quantrex Academy →

More from Hydrocarbons

In the following reaction sequence, Q , R , S and T are the major products. The correct statement(s) about Q , R , S and T is(are) 2026The List-II contains products obtained from the reaction of compounds in List-I with O ₃ /Zn- H ₂ O followed by cyclization (via more stable enolate) in the presence of aqueous NaO 2026Natural rubber on complete ozonolysis ( O ₃ /Zn- H ₂ O ) gives compound X as the major product. X gives positive iodoform and Tollen's tests. X on heating with aqueous NaOH gives Y 2026An optically active alkyl bromide C₄ H₉ Br, reacts with ethanolic KOH to form major compound [A] which reacts with bromine to give compound [B]. Compound [B] reacts with ethanolic 2026An alkane (Y) requires 8 moles of oxygen for complete combustion and on chlorination with Cl₂ /h , (Y) gives only one monochlorinated product (Z) . The total number of primary carb 2026R_f value for 2 -methylpropene in a solvent system (Ethyl acetate + ether) is 0.42 . 2 -methylpropene is treated with dilute H ₂ SO ₄ to give major organic product (X). R_f value f 2026Given below are two statements: Statement I: Methane can be prepared by decarboxylation of sodium ethanoate, Kolbe's electrolysis of sodium acetate and reaction of CH ₃ MgBr with w 2026Given below are two statements: Statement I: 3 -phenylpropene reacts with HBr and gives secondary alkyl bromide having a chiral carbon atom as the major product. Statement II: Aryl 2026 Full Hydrocarbons list All JEE Advanced PYQs