Answer
Ultraviolet
Explanation
The types of radiation and their wavelength are:
Gamma < 10⁻¹² m
X-rays 1 nm - 1 pm
Ultraviolet 400 nm - 1 nm
Visible 750 nm - 400 nm
Near-infrared 2.5 μm - 750 nm
Infrared 25 μm - 2.5 μm
Microwaves 1 mm - 25 μm
Radio waves > 1 mm
Hence, the given wavelength of 2.86 X 10⁻⁸ m corresponds to Ultraviolet.
A free-radical substitution reaction is likely to be responsible for the observations. The reaction mechanism of a reaction like this can be grouped into three phases:
- Initiation; the "light" on the mixture deliver sufficient amount of energy such that the halogen molecules undergo homologous fission. It typically takes ultraviolet radiation to initiate fissions of the bonds.
- Propagation; free radicals react with molecules to produce new free radicals and molecules.
- Termination; two free radicals combine and form covalent bonds to produce stable molecules. Note that it is possible for two carbon-containing free-radicals to combine, leading to the production of trace amounts of long carbon chains in the product.
Initiation
where the big black dot indicates unpaired electrons attached to the atom.
Propagation
Termination
Fusion, fission, and radioactive decays of unstable nuclei, involve release or absorption of energy. The total number of neutrons plus protons does not change in any nuclear process. are not conserved, but the total number of protons plus neutrons is conserved.