NEET2008Chemistryp Block Elements (Group 15, 16, 17 & 18)Actual
Which one of the following arrangements does not give the correct picture of the trends indicated against it?
Options
- AF ₂> Cl ₂> Br ₂> I ₂ : Oxidising power
- BF ₂> Cl ₂> Br ₂> I ₂ : Electron gain enthalpy
- CF ₂> Cl ₂> Br ₂> I ₂ : Bond dissociation energy
- DF ₂> Cl ₂> Br ₂> I ₂ : Electronegativity
Correct answer
C. F ₂> Cl ₂> Br ₂> I ₂ : Bond dissociation energy
Step-by-step solution
Key Idea : Generally bond dissaciation energies decreases in a group. Bond dissaciation energy also decreases with repulsion. array |l|c|c|c|c| X-X Bond & F - F & Cl - Cl & Br - Br & I - I Bond length (Å)) & 1.42 & 1.99 & 2.28 & 2.67 array l Bond dissociation energy ( kcal / mol ) array & 38 & 57 & 45.5 & 35.6 array In general the bond dissociation energy decreases as the bond length increases, but the bond dissociation energy of F ₂ is less than that of Cl ₂ . It is due to greater interelectronic repulsions betwee