Given below are two statements: Statement I: Due to increase in van der Waals forces, the order of boiling points is CH_3CH_2CH_2I > CH_3CH_2I > CH_3I. Statement II: As para-dichlorobenzene is more symmetric, its melting point is higher than ortho-dichlorobenzene, however its boiling point is lower than ortho-dichlorobenzene. In the light of the above statements, choose the correct answer from the options given below:
A. Both Statement I and Statement II are true
Statement I is true because as the size of the alkyl group increases, the molecular mass and surface area increase. This leads to an increase in the magnitude of van der Waals forces, which in turn increases the boiling point. Thus, the correct order of boiling points is CH _3 CH _2 CH _2 I > CH _3 CH _2 I > CH _3 I . Statement II is true because para-dichlorobenzene is more symmetrical than ortho-dichlorobenzene, allowing it to pack more efficiently in the crystal lattice, which results in a higher melting point. However, ortho-dichlorobenzene has a higher dipole moment than para-dichlorobenzene (which has a dipole moment of zero). The stronger dipole-dipole interactions in ortho-dichlorobenzene lead to a higher boiling point compared to para-dichlorobenzene. Both Statement I and Statement II are true. Answer: Both Statement I and Statement II are true
Related: Chemistry — Haloalkanes and Haloarenes · All PYQ Banks