InterviewSolution
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InterviewSolution
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Why does `ZnO` show increased electrical conductivity and turns yellow on heating?A. Frenkel defectB. Metal excess defectC. Metal deficiency defectD. Schottky defect |
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Answer» Correct Answer - B Zinc oxide is white in colour at room temperture. On heating it loses oxygenand turns yellow `ZnOoverset("heating")(to)Zn^(2+)+(1)/(2)O_(2)+2e^(-)` Now there is excess of zinc in the crystal and its formula becomes `Zn_(1+x)O`. The excess `Zn^(2+)` ions move to intrestitial sites and the electrons to neighbouring interstital sites . |
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