Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :
- Both Statement I and Statement II are true
- Both Statement I and Statement II are false
- Statement I is true but Statement II is false
- Statement I is false but Statement II is true
Answer
(1) Both Statement I and Statement II are true
Solution
Statement I: For the same halogen, the boiling point increases with the size of the alkyl group (larger surface area ⇒ stronger van der Waals forces): CH3CH2CH2I > CH3CH2I > CH3I ⇒ Statement I is true.
Statement II: As per NCERT, p-dichlorobenzene is more symmetric and fits more closely in the crystal lattice ⇒ higher melting point (p- 323 K; o- 256 K).
p-Dichlorobenzene is non-polar ( = 0) whereas o-dichlorobenzene is polar ⇒ weaker intermolecular forces in the p-isomer ⇒ lower boiling point (p- 448 K; o- 453 K) ⇒ Statement II is true.
Answer: (1)