Q. Propyne and propene can be distinguished by
A) $conc.H_{2}{SO}_{4}$
B) ${Br}_{2}\ in\ {CCl}_{4}$
C) $alk.{KMnO}_{4}$
D) ${AgNO}_{3}\ in\ {NH}_{3}$
Explanation
(d)
Propyne reacts with $AgNO_{3}\ in\ NH_{3}$ to give while ppt. of silver acetylide and propene does not react with it. (Only terminal alkynes react with$AgNO_{3}\ in\ NH_{3}$).
$CH_{3} - C \equiv CH + AgNO_{3} + NH_{3}$
Propyne
$\rightarrow CH_{3} - C \equiv C\ Ag$
silver acetylide
(white ppt.)
$CH_{3} - CH = CH_{2} + AgNO_{3} + NH_{3} \rightarrow no\ reaction$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.