Question
Write three reactions to show the acidity of alkynes.
Solution
(i) Action with sodamide: Acetylene reacts with sodamide to produce sodium acetylide and evolves ammonia.
(ii) Action with ammonical silver nitrate (Tollen's reagent): When acetylene is passed through ammonical silver nitrate, a white precipitate of silver acetylide is produced.
(iii) Action with ammonical cuprous chloride: When acetylene is passed through ammonical cuprous chloride, a red precipitate of cuprous acetylide is produced.
All these reactions indicate that acetylenic hydrogen atoms are acidic in nature.
(ii) Action with ammonical silver nitrate (Tollen's reagent): When acetylene is passed through ammonical silver nitrate, a white precipitate of silver acetylide is produced.
(iii) Action with ammonical cuprous chloride: When acetylene is passed through ammonical cuprous chloride, a red precipitate of cuprous acetylide is produced.
All these reactions indicate that acetylenic hydrogen atoms are acidic in nature.
