The correct sequence of bond enthalpy of 'C-X' bond is :
- CH3-Cl > CH3-F > CH3-Br > CH3-I
- CH3-F < CH3-Cl < CH3-Br < CH3-I
- CH3-F > CH3-Cl > CH3-Br > CH3-I
- CH3-F < CH3-Cl > CH3-Br > CH3-I
Answer
(3) CH3-F > CH3-Cl > CH3-Br > CH3-I
Solution
As per NCERT, the C–X bond length increases from F to I (size of halogen increases) ⇒ bond enthalpy decreases.
Bond enthalpies ( kJ mol-1): CH3-F 452, CH3-Cl 351, CH3-Br 293, CH3-I 234
∴ CH3-F > CH3-Cl > CH3-Br > CH3-I
Answer: (3)