What happens when sodium chloride crystals are heated with sodium vapour?
Answers
On heating sodium chloride with sodium vapors, the chloride ions diffuse to the surface of the crystals and combine with Na atoms which get ionized to Na+ ions by loosing electrons. These electrons get trapped in anion vacancies and act as F − centres which impact yellow colour to the atom.
the yellow colour acquired by the NaCl crystal is due to defect called metal excess defect due to anionic vacancy.
When crystals of NaCl is heated in an atmosphere of sodium vapour the sodium ion are deposited on the surface of crystal.The Cl- ion diffuse to form NaCl.This happens by loss of electron by Na to form Na+.The released electron diffuse into the crystal and occupy anionic site.these are called F centre and it imparts yellow colour to NaCl
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