why does the toothpaste doesnt react with tube in which its filled?
Because the inner side of the tube is designed not to react chemically with the contents (the same for remedies, facial creams etc, not only for tooth paste)
Toothpaste is inert. My years of experience as a dentist has shown me that even OUT of the tube, the paste is not real likely to have some kind of violent exothermic reaction.
toothpaste is inert. Plastic that makes up the toothpaste tube is inert. In order for a reaction to occur you have to have a reason (governed by the laws of thermodynamics). Chemical reactions are usually exchange of electrons (oxidation and reduction reactions) and if the two compounds are stable (i.e. have no free electrons to donate or no charges to attract electrons) they will not react.
