Answer to Question #127380 in Organic Chemistry for Ronald

Question

Acidic properties of alkynes using examples

Answer 1

Acidic properties of alkyne

Any Alkyne contains triple bond and it is SP hybridised . So hybrid carbon are more electronegative than simple carbon. In SP hybrid carbon electronegativity is 3.25 which becomes more electronegative than N but is less electronegative than oxygen. So when any sp³ hybrid carbon, we want to remove acidic hydrogen then it's conjugate base is comparatively more stable than simple other sp hybrid carbon.

Any Alkyne have in general p^ka around in range of 25. So it will be more acidic than hydrogen of nitrogen.

Data

Sp³ hybrid carbon - 2.5

Sp² hybrid carbon - 2.75

Sp hybrid carbon - 3.25

Ex.1.

If any electropositive element like Na reacts with acetylene then it forms disodium acetylide and hydrogen gas removes.

2. If acetylene reacts with AgNO₃ and NH₄OH then silver acetylide will formed as white ppt. and hydrogen gas remove here.