As compared with chlorocyclohexane, which of the following statements correctly apply to chlorobenzene? Choose the correct answer from the options given below :
- B, C and E Only
- A, C and E Only
- B, C and D Only
- A, D and E Only
Answer
(1) B, C and E Only
Solution
In chlorobenzene a lone pair of Cl is delocalised into the ring (resonance) and the C–Cl carbon is sp2 hybridised; in chlorocyclohexane the carbon is sp3 and there is no resonance.
A. Resonance moves electron density from Cl towards the ring the negative charge on Cl is less. Incorrect.
B. Resonance gives the C–Cl bond partial double bond character. Correct.
C. sp2 carbon is more electronegative and Cl donates electrons by resonance the C–Cl bond is less polar (dipole moment of chlorobenzene 1.69 D, lower than that of chlorocyclohexane). Correct.
D. Partial double bond character and the smaller sp2 carbon make the C–Cl bond shorter (169 pm in chlorobenzene against 177 pm in an alkyl chloride), not longer. Incorrect.
E. The C–Cl bond uses an sp2 hybrid orbital of carbon. Correct.
B, C and E only.
Answer: (1)