Question

Th e energy required to break one mol of Cl-Cl bonds in Cl₂ is 242 kJmol^-1​​​​​​. The longest wavelength of light capable of breaking a single Cl-Cl bond _{​​​​​​} is

A. 594nm

B.640nm

C. 700nm

D.494nm

Answer 1

Answer:

494nm

Explanation:

Cl2→2Cl⋅

ΔH=+242xkJ/mol

I will work out the energy required to dissociate 1 molecule of Cl2:

E=242×1036.022×1023=4.0186×10−19xJ

Now I use the Planck Expression:

E=hf=hcλ

∴λ=hcE

λ=6.63×10−34×3×1084.0186×10−19xm

λ=4.94×10−7xm

λ=494nm


hope this helps :)