Question

When 2-butyne is treated with $H_2/$Lindlar's catalyst, compound $X$ is produced as the major product and when treated with $Na/$liq. $N{H}_3$ it produces $Y$ as the major product. Which of the following statements is correct?

• A. $X$ will have higher dipole moment and higher boiling point than $Y$
• B. $Y$ will have higher dipole moment and higher boiling point than $X$
• C. $X$ will have lower dipole moment and lower boiling point than $Y$
• D. $Y$ will have lower dipole moment and lower boiling point than $X$

Answer 1

The correct option is A $X$ will have higher dipole moment and higher boiling point than $Y$

As we learnt,

Birch Reduction:

Alkynes on reduction with sodium in liquid ${NH}_3$ form trans alkene where in

Reduction of alkynes.

Proceeds via two single electron transfer from $Na$ to alkyne each followed by protonation with ${NH}_3$.

Cis have higher dipole moment than trans option $1$ is correct. i.e,

$X$ will have higher dipole moment and higher boiling point than $Y$.