Anonymous asked in Science & MathematicsChemistry · 10 years ago

When excess hydrogen bromide gas is mixed with 2-butyne, a possible product is? multiple choice?

a) 1,2-dibromobutane.

b) 2,3-dibromobutane.

c) 2,2-dibromobutene.

d) 1,3-dibromobutane.

1 Answer

  • Anonymous
    10 years ago
    Favorite Answer

    2-butyne is CH3-CEC-CH3... where E represents a triple bond.

    If you add two equivalents of HBr, you will be able to brominate the alkyne twice (first time into an alkene, and second time to saturate it). Notice that place where you can add Br is carbons # 2 and 3, because that's where the unsaturation (triple or double bond) exists.

    Any answer that places the Br on carbon #1 or 4 is not plausible. Eliminate answers A and D.

    If you brominate twice, you will bet an halogenated alkane, not an alkene. Elminate answer C (notice the "-ene" suffix).

    Answer choice B is the only answer choice that gives a possible product. Another possibility is 2,2-dibromobutane, but that's not a choice here.

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