Tue April 24, 2012 By: Jigyasa Dwivedi

why NaCL acquires yellow colour on heating in an atmosphere of Na ?

Expert Reply
Tue April 24, 2012
When NaCl is heated in Na vapor, the excess sodium deposits on the surface. Cl- diffuses to the surface where they combine with the Na atoms. These Na atoms lose the electrons. The electrons diffuse into the unoccupied site produced. The electrons absorb some energy from the white light and then re-emit it as the yellow color. 
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