NEET
- Exam
- NEET
- Subject
- Chemistry
- Chapter
- Haloalkanes and Haloarenes
NEET · Chemistry · Haloalkanes and Haloarenes
Given below are two statements: Statement-I : Boiling point of...
Given below are two statements:
Statement-I : Boiling point of isomeric dihalo benzenes are very nearly the same, However, the para isomers has high melting point as compared to their ortho and meta isomers.
Statement-II : It is due to symmetry of ortho isomers that fits in crystal lattice better as compared to para and meta-isomers.
In the light of the above statements, choose the most appropriate answer from the options given below:
Options
- ABoth statements-I and II are correct.
- BBoth Statement-I and II are incorrect
- CStatement-I is correct but Statement-II is incorrect.
- DStatement-I is incorrect but Statement-II is correct.
Correct answer
C. Statement-I is correct but Statement-II is incorrect.
Step-by-step solution
Statement-I is correct: The boiling points of isomeric dihalobenzenes (ortho, meta, and para) are indeed very similar due to their similar molecular weights and intermolecular forces. However, the melting points differ, with the para isomer typically having a higher melting point than the ortho and meta isomers.
Statement-II is incorrect: The correct reason for the higher melting point of the para isomer is due to its symmetry, which results in stronger intermolecular forces (London dispersion forces) and a more efficient packing in the crystal lattice, not the ortho isomer.
The symmetry of the para isomer allows for:
- Better alignment of molecules
- Stronger intermolecular interactions
- Higher lattice energy
This results in a higher melting point for the para isomer compared to the ortho and meta isomers.
So, the correct option is (3).