Question

Explain why Surface of some metal acquire a dull appearance after exposed in atmosphere for long time ?​

Answer 1

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✨Surface of some metals acquires a dull appearance because they react with air or water in the environment to form undesirable compounds (such as Oxides) . This process is called Corrosion.

✨For example:- silver tarnishes, copper Develops green coating, iron loses its lustre. The Corrosion of iron is called Rusting. The chemical formula of Rust is Fe2O3.xH2O

Answer 2

Answer:-

The surface of some metals acquires a dull appearance when exposed to air for a long time due to the formation of a thin layer of oxide, carbonate or sulphide on their surface by the slow action of the various gases present in air