NTA Abhyas NEET2020Chemistryp Block Elements (Group 15, 16, 17 & 18)Practice
Which one of the following orders is not in accordance with the property stated against it ?
Options
- AF 2 >Cl 2 >Br 2 >I 2 : Bond dissociation energy
- BF 2 >Cl 2 >Br 2 >I 2 : Oxidising power
- CHI>HBr>HCl>HF: Acidic property in water
- DF 2 >Cl 2 >Br 2 >I 2 : Electronegativity
Correct answer
A. F 2 >Cl 2 >Br 2 >I 2 : Bond dissociation energy
Step-by-step solution
Bond energy ∝ Bond strength Bond strength ∝ overlapping ∝ 1/Energy Level F - F Cl - Cl Br - Br I - I 2p-2p 3p-3p 4p-4p 5p-5p So, the order of bond energy should be F 2 >Cl 2 >Br 2 >I 2 But in case of the lower value of bond dissociation energy of fluorine is due to the high inter-electronic repulsions between non-bonding electrons in the 2p- orbitals of fluorine. As a result, F − F bond is weaker in comparison to Cl − Cl and Br − Br bonds. So, the correct order of bond dissociation energy is Cl