d
When \(2-\) butyne is treated with \(H_2/\) Lindlar's catalyst, compound \(X\) (cis \(-2-\) butene) is produced as the major product; and when treated with \(Na/liq\,NH_3\) it produces \(Y\) (trans \(-2-\) butene) as the major product. Cisisomer \((X)\) will have higher dipole moment and higher boiling point than trans \((Y)\).