Question

Zno turns yellow on heating . give reasons with reaction involved

Answer 1

the thermochorism of Zno result from a mirror loss of oxygen upon heating to temperature around 800 ℃ i.e a non-stoichiometric Z n
+xO with x=7×10^-5

Answer 2

ZnO turns yellow on heating due to loss of oxygen to the environment at high temperature to form the non stoichiometric defect due to this anionic vacancies are created and when an electron occupies(F centre) that vacancy it imparts yellow colour.
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