2006-11-25 23:00:56 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Other - Science
When our good white paper is prepared it is bleached.This removes all colour from it or chemically the present oxygen.But after a long period of time after this paper is exposed to air,the oxygen molecules are regained and the old colour comes back.
This is because generally CaOCl2 (bleaching powder) or SO2 is used.When a stronger bleacher is used the regaining of colour wont happen.
2006-11-26 03:33:30 · answer #1 · answered by vishnukmd 1 · 0⤊ 1⤋
white
2017-03-22 03:36:35 · answer #2 · answered by maha 7 · 0⤊ 0⤋
I would guess it is from the effects of oxygen on the paper which causes oxidation and thus causes the yellow color.
2006-11-25 23:04:07 · answer #3 · answered by Shaad 3 · 0⤊ 0⤋
the air ages the wood pulp in the newsprint by activating the natural acids in it...newsprint was never designed to be preserved....the older stuff sometimes doesnt because of the high ragweed content.
2006-11-25 23:10:31 · answer #4 · answered by koalatcomics 7 · 0⤊ 0⤋
Due to oxidatin with oxygen present in air.
2006-11-25 23:21:03 · answer #5 · answered by lineup2007 1 · 0⤊ 0⤋
Jaundice.
2006-11-25 23:04:08 · answer #6 · answered by terry t 6 · 0⤊ 0⤋
it is due to the action of microbes to the organic part of the paper
oxidation takes place due to it
2006-11-25 23:06:08 · answer #7 · answered by ashish.prshr 2 · 0⤊ 0⤋