An alkene has a pK_a of 40, while an alkyne has a pK_a of 25. Which functional group is more acidic? A) an alkyne, because it has a higher pK_a B) an alkyne, because it has a lower pK_a C) an alkene, because it has a higher pK_a D) an alkene, because it has a lower pK_a E) They have the same acidity.

Question

Quizplus · Accepted Answer

The lower the pK_a, the stronger the acid. Therefore, the alkyne with a pK_a of 25 is more acidic than the alkene with a pK_a of 40. Choice A and C are incorrect because they incorrectly state that the higher pK_a value is more acidic. Choice D is incorrect because it incorrectly states that the alkene has a lower pK_a when it actually has a higher pK_a. Choice E is incorrect because the two functional groups have different acidities.

An Alkene Has a PKa of 40, While an Alkyne

An Alkene Has a PK_a of 40, While an Alkyne