# How does a terminal alkyne react in a Grignard reaction, will the carbonyl carbon attack the terminal carbon?

Actually, the pKa of acetylene for example, is $25$, but the pKa of a Grignard reagent is generally much higher than 50~60 (because it's pretty much the conjugate base of an alkane!).
And that deactivates the Grignard reagent. Whoops! The acetylide can still be a pretty nice nucleophile, but not quite as great. The 25~35 orders of magnitude in the pKa is quite a large difference!