Question

Describe a distinguish test between but-1-yne and but-2-yne

Answer 1

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The Cu will react with but-1-yne to form a red-brown precipitate and the but-2-yne will not react. If you have a mixture of the two, this can be used to separate them.

Yes, it can be done by oxidation with either ozone or KMnO4, but the procedure using Cu + is easier and faster.