JAMB - Chemistry (1992 - No. 40)
Which of the following compounds reacts with sodium metal as well as silver and copper salts ?
CH3C Ξ C—CH3
CH3CH2CH23>
CH3C Ξ CH
CH3CH = CH CH3
Vysvětlení
Propyne (CH\(_3\)C≡CH) reacts with sodium metal, and also with silver and copper salts. Propyne, being a terminal alkyne, has a relatively acidic terminal hydrogen. This acidity allows it to react with strong bases like sodium metal to form sodium acetylide. The acetylide anion formed in the reaction with sodium metal can be isolated and reacted with silver or copper salts to form insoluble silver and copper acetylides. These precipitates are useful for identifying the presence of terminal alkynes.