Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
MHT CET202525 Apr 2025Evening ShiftChemistryHydrocarbonsActual

Identify 'A' in the following reaction. A Lithium amide Ethynyl lithium Bromoethane But -1- yne

Options

  1. AEthene
  2. BEthyne
  3. CBut-1-ene
  4. DBut-2-ene

Correct answer

B. Ethyne

Step-by-step solution

Reverse analysis begins with the product but-1-yne: CH ₃ CH ₂ C CH . It forms from ethynyl lithium ( Li-C CH ) and bromoethane ( CH ₃ CH ₂ Br ) via nucleophilic substitution: Li-C CH + CH ₃ CH ₂ Br CH ₃ CH ₂ C CH + LiBr Ethynyl lithium is derived from A and lithium amide: The strong base LiNH ₂ deprotonates terminal alkynes. Since ethynyl lithium is formed, A must be ethyne ( HC CH ): HC CH + LiNH ₂ Li-C CH + NH ₃ Among the options—ethene, ethyne, but-1-ene, but-2-ene— ethyne is compound A .

Practice Hydrocarbons on Quantrex Academy →

More from Hydrocarbons

What is the major product [ P₃ ] formed when n- Hexane undergoes the given series of reactions: n-Hexane V₂O₅; 20 atm, 773k [ P ₁] C₂H₅Cl, Anhyd.AlCl₃; [ P ₂] Conc.HNO₃ + H₂SO₄; 33 2026The statements given below contains assertion and reason. Choose the correct option Assertion (A): Propene reacts with HBr in presence of organic peroxide gives 1-bromopropane. Rea 2026The product formed in the following reaction is: 2026Arrange the given alkanes in increasing order of their boiling points. (A) 2, 2-dimethylpropane (B) 2-methylbutane (C) n -pentane (D) n -butane 2026Select the reagents needed to convert Benzene to 4–Bromophenylpropene in the correct sequential order. (A). Cl ₂/ (B). ( CH ₃)₂ -CHCl /anhyd. AlCl ₃ (C). Alc. KOH (D). Br ₂ / Fe 2026The decreasing order of reactivity towards electrophilic substitutions is: 2026A compound with molecular formula C ₅ H ₁₀ that gives acetone on ozonolysis is: 2026When 2-butyne is treated with dilute H ₂ SO ₄/ HgSO ₄ , the product formed is: 2026 Full Hydrocarbons list All MHT CET PYQs