Question

which compound will give red precipitate with cu2cl2 and nh4oh

Answer 1

Only Terminal alkyne gives red ppt with Cu2Cl2 +NH4OH

Answer 2

Hey dear,

● Answer -
Acetylene

● Glaser coupling -
- This reaction was first observed by Carl Andreas Glaser
- It's identification test for terminal alkynes.
- In this reaction, an terminal alkyne reacts with basic cupric chloride and on subsequent oxidation in air gives diyne.

- For example, acetylene couples with itself in presence of ammoniacal cuprous chloride to produce but-1,3-yne (red brown ppt).
2 CH≡CH ---> CH≡C-C≡CH

Hope this helps you...