Account for the following: (a) some of glass object recovered from an

1.	Account for the following: (a) some of glass object recovered from ancient monuments look like milky instead of being transparent (b)Zinc oxide is white but turn yellow on heating. Explain
Answer» (a) Due to annealing over a number of years glass acquires some crystalline character (b) because it loose oxygen ZnO →Zn²⁺ + 1/2O₂ + 2e Metal excess defect electron in interstitial voids the colour is yellow as the remaining colour of white light are absorbed by these electron.

Account for the following: (a) some of glass object recovered from ancient monuments look like milky instead of being transparent (b)Zinc oxide is white but turn yellow on heating. Explain

Answer»

(a) Due to annealing over a number of years glass acquires some crystalline character

(b) because it loose oxygen

ZnO →Zn²⁺ + 1/2O₂ + 2e

Metal excess defect electron in interstitial voids the colour is yellow as the remaining colour of white light are absorbed by these electron.