When 2-butyne is treated with H₂/ Lindlar’s catalyst, compound X is produced as the major product and when treated with Na/liq.NH₃ it produces Y as the major product. Which of the following statements is correct?

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

When 2-butyne undergoes hydrogenation with H₂ in the presence of Lindlar's catalyst, it forms a cis-alkene, specifically cis-2-butene (compound X). In contrast, when treated with sodium in liquid ammonia, it produces trans-2-butene (compound Y). The properties of these compounds can be analyzed based on their molecular structure.

Comparing Properties of X and Y

To determine which statement is correct, we need to consider the following:

• Dipole Moment: Cis-2-butene (X) has a higher dipole moment due to its polar structure, while trans-2-butene (Y) is more symmetrical and has a lower dipole moment.
• Boiling Point: The boiling point is influenced by the dipole moment and molecular interactions. Generally, cis isomers have higher boiling points than their trans counterparts due to stronger dipole-dipole interactions.

Conclusion on the Statements

Given the above points, we can analyze the options:

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

Thus, the correct answer is D: X will have higher dipole moment and higher boiling point than Y.