The reduction of 3-hexyne with `H_(2)`/Lindlar’s catalyst gives predominantly -

Lindlar’s catalyst consists of -

Reduction of 2 - butyne with sodium in liquid ammonia gives predominantly

But- 2 -ene reacts with H_(2) in the presence of Lindlar's catalyst. The predominant product of reaction is

2-Butyne on catalytic reduction with Lindlar's catalyst gives mainly .......... product.

Reduction of 2-Butyne with Na in liquid NH_3 gives predominantly: