O2 undergoes photochemical dissociation into one normal oxygen atom and one oxygen atom,1.2 eV more energetic than normal. The dissociation of O2 into two normal atoms of oxygenrequires 482.5 kJ/mol. The maximum wavelength effective for photochemical dissociation of O2 is

The energy required to dissociate O2 into two normal oxygen atoms is given as 482.5 kJ/mol. We need to convert this energy into electron volts (eV) for easier calculations.

1 eV = 96.485 kJ/mol

So, 482.5 kJ/mol = 482.5/96.485 = 5 eV

The energy required to dissociate O2 into one normal oxygen atom and one oxygen atom 1.2 eV more energetic than normal is therefore 5 eV + 1.2 eV = 6.2 eV.

The energy of a photon is given by the equation E = hc/λ, where h is Planck's constant (4.1357 x 10^-15 eV.s), c is the speed of light (3 x 10^8 m/s), and λ is the wavelength.

Rearranging the equation for λ gives λ = hc/E.

Substituting the values gives λ = (4.1357 x 10^-15 eV.s x 3 x 10^8 m/s) / 6.2 eV = 2 x 10^-7 m or 200 nm.

Therefore, the maximum wavelength effective for photochemical dissociation of O2 is 200 nm.