Bond energies can be obtained by using the following relation: `DeltaH (reaction) = sum`Bond energy of bonds, broken in the reactants `-sum` Bond energy fo bonds, formed in the products
Bond enegry depends on three factors:
a. Greater is the bond length, lesser is the bond enegry.
b. Bond energy increases with the bond multiplicity.
c. Bond enegry increases with electronegativity difference between the bonding atoms.
Use the bond enegries to estimate `DeltaH` for this reaction:
`H_(2)(g) +O_(2)(g) rarr H_(2)O_(2)(g)`
`{:("Bond","Bond energy"),(H-H,436 kJ mol^(-1)),(O-O,142 kJ mol^(-1)),(O=O, 499kJ mol^(-1)),(H-O,460kJ mol^(-1)):}`

Explanation

This may be attributed to `l.p-l.p` repulsions due to small size of F atom.