Question

Why do alkynes under go nucleophilic addition reaction . while simple alkynes don't do so.

Answer 1

Alkynes can follow nucleopilic addition due to high electronegativity of triple bonded carbon. (50% S character).
But such addition is not directly possible due to presence of electron clouds. Therefore it requires heavier metals like Hg, Ba , Pb, No (in ionic form which decrease electron density around triple bond.