Acommon way of initiating certain chemical reactions with light involves the generation of free halogen atoms in solution. if δh for the reaction cl2(g) → 2cl(g) is 242.8 kj/mol, what is the longest wavelength of light that will produce free chlorine atoms in solution?

The longest wavelength of light that will produce free chlorine atoms in solution is 493 nm.

Explanation:

Energy required to produce free chlorine atoms from one mole of chlorine gas :

= 242.8kJ = (1kJ=1000J)

1 mole = molecules

For molecules = 242,800 Joules

For one molecule of chlorine gas =  

According to photoelectric equation:

E = Energy of the photon of light used to produce free chlorine atoms

= frequency of the light used to produce free chlorine atoms

h = Planck's constant =, c = speed of light=

= wavelength of the light used to produce free chlorine atoms

The longest wavelength of light that will produce free chlorine atoms in solution is 493 nm.