NEET2002Chemistryp Block Elements (Group 15, 16, 17 & 18)Actual
Assertion : F - F bond has low bond dissociation energy. Reason : The fluorine has lower reactivity.
Options
- AIf both the assertion and reason are true and reason is a correct explanation of the assertion.
- BIf both assertion and reason are true but assertion is not a correct explanation of the assertion.
- CIf the assertion is true but the reason is false.
- DIf both assertion and reason are false.
Correct answer
C. If the assertion is true but the reason is false.
Step-by-step solution
Lower value of bond dissociation energy of fluorine is due to the high inter electronic repulsions between non-bonding electrons of the 2 p -orbital of small sized fluorine. As a result F - F bond is weaker as comparison to Cl - Cl and Br - Br bonds. array lr & Bond dissociation energy F - F & 38 ~K cal / mole Cl - Cl & 57 ~K cal / mole Br - Br & 45.5 ~K cal / mole I - I & 35.6 ~K cal / mole array