Which of the following has the lowest pK_a? A) butane B) 1-butene C) 1-butyne D) 2-butyne

Question

Quizplus · Accepted Answer

1-butyne has the lowest pKa among the options, indicating it is the most acidic. This is because the sp-hybridized carbon in 1-butyne can better stabilize the negative charge in its conjugate base compared to the sp2 in 1-butene and the sp3 in butane. 2-Butyne also has an sp-hybridized carbon, but the terminal alkyne in 1-butyne is more acidic due to the inductive effect of the additional alkyl group in 2-butyne slightly reducing its acidity.

Which of the Following Has the Lowest PKa

Which of the Following Has the Lowest PK_a