CGPET 2014 Solved Paper

CH3CH2C≡CH‌

A

⇒

B

CH3−C≡C−CH3

CH3CH2C

but−1−yne

≡CH‌ ‌

Ethanoilic‌"‌KOH

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[CH3‌CH

Intermediate

=C=CH2]⟶

CH3C≡CCH3

but−2−yne

Acetylene homologues isomerise when heated with ethanolic KOH, the triple bond moving towards the centre of the chain.
When alkynes are heated with sodamide in an inert solvent (paraffin), triple bond shifts towards the end of the chain.