Question

Zinc become dull in contact of moist air why?

Answer 1

Zinc in presence is moist air is coated by the thin film of its basic carbonate on its surface and becomes dull.

4Zn + 3H2O + 2O2 + CO2 = ZnCO3.3Zn(OH)2

Answer 2

Concept:

Oxidation, according to classical or older concepts, is a process that involves the addition of oxygen or any other electronegative element, or the removal of hydrogen or any other electropositive element.

The process by which an atom or ion loses one or more electrons is characterised by the electronic notion of oxidation.

Solution:

Zinc is dulled by a thin coating of its basic carbonate on its surface when it is exposed to moist air.

$4Zn+3H_2O+2O_2+CO_2 \rightarrow ZnCO_3.3Zn(OH)_2$

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